LOS ANGELES — Matthew Perry had much to teach his 17 Again co-star Zac Efron. At least when it came to video games.
"The biggest advice I had for him was to start playing Fallout 3 instead of Call of Duty 4. It has more of a story," Perry deadpans with the same comic timing that made him a star on Friends.
"Dude, I could not figure it out!" Efron shoots back as they riff off each other at the Four Seasons Hotel in Beverly Hills.
All jokes aside, Perry, 39, was ready to provide Efron with advice, but he says it wasn't necessary. "He's got his head on straight. It would be very easy to sort of be a jerk or to get a little bit too lost in all this attention, but that never really seemed the case," Perry says.
Still, Efron insists he learned about more than just games from Perry, who plays the older version of him in the film. "It's always encouraging to see people who have been successful in the business for a long time who remain grounded, who remain real people and normal and kind and still hardworking," Efron says.
Perry is the latest mentor to dispense wisdom to the 21-year-old, who achieved heartthrob status with his role as a basketball captain in Disney's High School Musical.
Leonardo DiCaprio's recent warning to him: Don't do heroin. That's the only way the former teen idol sees the box-office stud blowing his shot at a lengthy career. "Just coming from Leo, he's just really laid-back, and he just casually put that out there just like, 'Oh yeah, one more thing,' " Efron says.
Efron and Perry met for the first time at a table read for the film.
"I didn't know who you were. I heard, 'This guy's a big deal,' " says Perry, who was impressed by Efron's work ethic. "He got appendicitis while shooting and apologized about taking a day off, and then was right back at work. That's pretty cool."
Efron acknowledges that people often expect him to act like a diva. "See, that's the annoying part. People honestly think like that. It's so funny ... 'cause I know I'm not a big deal!"
Efron plays a high school basketball player in this film, like High School Musical, but he maintains he is not being typecast. This time, he's a 37-year-old who is trapped in a teen's body.
"It was not a typical high school movie or another musical. I knew it would be a stretch. I think it's important (to mix it up). That's what Seth Rogen does a lot. You're genuinely surprised by his choices and how good he is," says Efron, who met Rogen's frequent collaborator Judd Apatow during the shoot.
Efron seduces Apatow's real-life wife, Leslie Mann, in the film. "Every time it was a remotely intimate scene with Leslie, Judd would show up on set that day. I hope at some point I get to work with Judd, and this is of course the way that I get to meet him. I didn't even talk to Leslie unless we were in a scene together. (I stayed) far, far away."
Does Efron think it's realistic to find happily ever after with your high school love? "For a high percentage of people, it does ultimately work out," says Efron, who has been dating his High School Musical co-star Vanessa Hudgens since 2006.
But when it comes to their future together, he's mum. "Everyone's different," he hedges before Perry swoops in. "That's a very big, bold choice to make before you're out there in the world and you're going to go out there together," Perry says of marrying young.
As he approaches his 40th birthday, though, the bachelor says, "I can kind of picture (settling down)." He has been getting "on-the-job training" as a godfather to his best friend's son. "I like to think that I'd be kind of a hip, cool dad, (but) if I had a daughter, I'd be the overprotective, 'You're not going out with anyone until you're 30!' kind of dad."
Efron says he probably will emulate his own parents. "They were pretty strict, but they gave us a lot of opportunities. My dad taught me a lot of things, like I pretty much tried every sport by the age of 10, which is cool. I hope that's the kind of dad I can be." But then he stops himself, "Why am I even talking about being a dad?"
As for the more immediate future, Perry is plotting a return to television with his pilot, The End of Steve, which he co-wrote. And Efron hopes to re-team with 17 Again director Burr Steers for the drama The Death and Life of Charlie St. Cloud. "I want to pick up where we left off," says Efron, who recently dropped out of a remake of Footloose to try something new. "Everyone's asked, 'You want to change your image, right? You want to be dramatic.' That's not what it's about. I want to make a cool movie and that could be a hundred different things, so we'll see."
USA Today: Efron would change a few things if he were '17 Again'
LOS ANGELES — It wasn't that long ago that Zac Efron was 17 years old, but there are a few things he wouldn't mind re-doing.
"I could do prom better; I would definitely give that a retry," said Efron, 21, at the premiere of his new movie, 17 Again. "And I'd ace my SATs. But I think I'm for the most part proud of the way I lived my high school experience. Even the biggest mistakes that I made — they were probably what got me here today."
But why prom?
"Eh, I'd probably be a bit more debonair. I'd be the guy in the circle," he said laughing, as girlfriend Vanessa Hudgens walked behind him.
There was much back-in-the-day contemplation Tuesday night at the Hollywood premiere of the film, which opens Friday.
"What's so funny is I wouldn't go back to 17. I think everything that you experience in your life makes you the person you are today," said Michelle Trachtenberg. "I'm now over 21, so I can enjoy a glass of wine with dinner, and at 17 I was mostly flat-chested, and I think I'm doing pretty good now!"
Matthew Perry, who plays the older version of Efron's character, wasted no time ticking off what he'd do if he were that young again.
"Having met Zac, I would go to the gym! I would go straight there. He's buff," he said.
Leslie Mann, who plays Efron and Perry's wife in the movie, said she'd rethink her high school dating life.
"I had a boyfriend for about four years for the entire time I was in high school. I think I might go back and maybe date him for a year and half and for the rest of the time date a whole array of other boys," she said.
And what was working with Efron as a love interest like?
"I think it creeped my daughter out. My daughter — her whole room is Zac Efron posters everywhere," she said. "But he's a great guy; he's truly one of the nicest guys you'll ever meet. He's really a hard worker, really great attitude. "
Judd Apatow, Mann's writer and director husband, said that he has "spent my entire life trying to rewrite my history in my work, so I'd do all sorts of stuff differently! That's why I'm in the business. And hey, if my pain amuses you, it was worth it on some level."
One thing he might regret, he joked, is allowing his wife to actually be in this film.
"I think my wife is fantastic in the movie, but somehow you believe she's hot for Zac Efron in it. I don't know how she pulled off that bit of acting magic," he said. "She's taken it home too. She still is hot for Zac Efron around the house. She hums Get Your Head in the Game when she kisses me."
People: Zac Efron ... Answers Your Questions
A record number of fans sent their burning questions to PEOPLE.com for Zac Efron, who stars in this month's comedy, 17 Again. The actor, 21, responds here – covering topics ranging from keeping that hot body to partying with his grandma.
• I read somewhere that you recently bought your first home. Has anything surprised you about homeownership?
REBECCA WOODS, Chicago, Ill.
Efron: My sprinkler broke the other day, and I spent all day trying to fix it. I just made things worse and now my whole back yard is flooded. And keeping the house clean. It's like a bigger version of the disaster formerly known as my room.
• What is your workout routine and diet?
JOSH BRIMMEIER, Ames, Iowa.
Efron: I like backpacking, hiking, surfing, swimming, playing tennis – things that get you active and are also fun. If I do go to the gym I usually do circuit training. If you're skinny, you should never stop eating. The problem is a lot of people mistake that for permission to eat junk food. I try not to eat anything that's packaged. Of course, I never succeed.
• First of all, I think you are insanely hot. My question is: Did you ever cause trouble when you were 17?
NICOLETTE FAVARATO, East Longmeadow, Mass.
Efron: Sure! I think I put my parents through some grief. When I was 17, I was too demanding of freedom; I wanted an unnecessarily long leash. Don't push it too hard, because you're going to need your parents in college when you're broke!
• What did you want to be when you grew up?
JOSHUA AND LILI GALVAN. Kyle, Tex.
Efron: When I was a kid, I wanted to be a professional baseball player, or an astronaut, or be in the X Games. I thought Tony Hawk was the coolest guy alive.
• What keeps you motivated?
KRISTIE, Tallahassee, Fla.
Efron: I've always enjoyed being creative, no matter what it is. Anything that I do in life, I always want to do it well. That leads to a lot fun adventures!
• I'm a big fan. I especially loved watching you sing in Hairspray and High School Musical. Would you ever consider releasing an album of your own?
ERIN STRECKER, Des Moines, Iowa
Efron: I'm not going to pretend that I'm a music prodigy. I would want an album to come from me, not from writers or other producers. I definitely don't possess those skills and right now. I just don't have the time.
• Hey Zac! If you could only eat one thing for the rest of your life, what would it be?
DANIKA BODNARCHUK, St. Albert, Alberta, Canada
Efron: Peanut butter and jelly sandwiches … and milk.
• If you were able to costar with any actor dead or alive, who would it be and why?
NNEKA CHARLES, Brooklyn, N.Y.
Efron: Oooh, it would be fun to work with Marlon Brando or James Dean. Brando had this ability to be real but interesting.
• What did you have for breakfast this morning?
EMMY JEPSON, England
Efron: It was in a hotel. I had poached eggs on white toast with ketchup, and then I had oatmeal, and then a strawberry banana smoothie.
• How come we rarely see you out partying like the other young Hollywood stars?
MORGAN STEVENS, Westlake, Ohio.
Efron: I'm not really into partying. Don't get me wrong – I've gone to a club. But I'd much rather be with my close friends at home or a concert, or on a trip. I'll go dancing with my grandma. She likes to cut a rug!
• You play a man who has the chance to be 17 again. Are there any ages that you would want to go back to, that you would want to revisit in your life or that you would want to skip?
ASHLEY LIZZETTE TORRES, Whittier, Calif.
Efron: I think it's important to remember to live in the moment and enjoy every day to the fullest. Don't sweat the small stuff and don't cry over spilled milk.
For more Zac's answers – to questions about romance, hair care and his career – pick up this week's issue of PEOPLE, on newsstands Friday
CanMag: Tom Lennon on 17 Again
Reno 911’s Thomas Lennon came up with an all new quirky character for 17 Again. He plays Matthew Perry’s best friend, a sci-fi geek who became rich as an adult. When his friend reverts to his high school self, it takes a battle of epic movie memorabilia to convince him that real magic has occurred.
“We rehearsed that scene for about a month every single day in the parking lot of an Arby’s in Hollywood with sticks,” Lennon said. “Zack really, really hurt me pretty badly one day on the shoot nailing me in the head. I think it was just a warning, just a reminder. I wasn’t that bright to begin with before that injury. Insurance says I can’t do anything about it.”
It helped Lennon’s character to have a cool friend in high school. That might be another fiction of Hollywood. “As an actual nerd who played the cello, wore a lot of tinted Clearasil on my face and bow ties, I never had the sort of actual Zac Efron type take me under his wing, which would have been a wonderful experience. I’m sure I would have done better with the ladies. But no, I was mostly flying solo with the cello and the bow ties. I did not have this kind of actual friendship. It would have been nice.”
Lennon’s character speaks Elvish, but legal issues kept him from speaking authentic Tolkien language in the film. “The Elvish is actually an ancient form of Irish because Elvish is a registered trademark of the Tolkien family and you can’t use it. So what we’re speaking is an ancient form of Gaelic or Irish. The way I prepared is I had it on an iPod. I listened to it day and night for weeks leading up to the scene and then I got there and Melora Hardin hadn’t worked on it at all. So, she had hers written on the plate in front of her.”
Efron was modest, but Lennon sang praises of his professional behavior above and beyond the call of duty. “The day that struck me the most was the day that Zac came back. He took one day off to almost die from an appendicitis and then came immediately back to work the next day like at 8 a.m. and that scene is the scene in the courthouse where he reads the letter to Leslie’s character. I just thought, wow, that’s unbelievably impressive because he literally came basically from the hospital that night to the set that morning and did that scene, the courthouse scene at the end of the movie that’s I think so incredibly moving and that’s something that will always stick around with me.”