School's out for Zac Efron

The heartthrob lead from Disney's teen musicals has graduated to adult romcom. He tells Gill Pringle why he hated Leonardo DiCaprio

Which is why High School Musical's star Zac Efron is taking his tips from pin-up predecessors like Johnny Depp and Leonardo DiCaprio in planning a career to transcend the curse of pubescent success.

Efron, 21, smartly severs the Disney umbilical cord with 17 Again; his first foray into the semi-adult world of romantic comedy, in which he is romantically paired with an actress twice his age. And while his devoted teenage fans will doubtlessly still flock to the cinema, it's a smooth move toward reaching out to an older audience; more specifically, towards older women.

"Since I was very young, I've always got along with adults as well as, if not better, than kids my own age. I don't know why that should be?" he asks coyly. "Throughout HSM, there's been a teenage following. But even more than that, there's been the moms right from the very beginning. The more interesting fan encounters are usually with moms," he continues.

"As far as the mothers are concerned, you never know what's going to happen. Its funny because the kids can be shy but the moms feel like they know you. They come across as very comfortable. They want to talk to me and ask how I'm doing, and sometimes they want to go and get a bite to eat... Oh yeah, a lot of stuff like that," he says, nodding his head slowly for emphasis before proceeding to demonstrate the distinctly teen skill of "talk and text".

"The trick to secret texting is all about positioning," he says lowering his iPhone to just below the top of the table in his Beverly Hills hotel suite. From this position, he stares directly into my eyes while, hidden from view, his fingers move furiously, writing and sending a text at the same time. "Look!" he says triumphantly, sliding his phone across the table moments later. "And barely any spelling mistakes!"

It's a rare spontaneous moment in the precision-coordinated life of this man-child, whose playful smile, deep blue eyes and cute haircut have launched an entire Disney franchise. He played HSM's fleet-footed high school basketball star Troy Bolton, in the made-for-TV movie that not only broke all cable-TV records but made history by crossing over to the big screen, where HSM3 would break further records for the highest grossing opening weekend for a musical.

For Efron, the result has been an almost total absence of privacy for the past three years.

"It's something you can't really deal with, and the more people that get involved, trying to curb, say the paparazzi for instance, the hairier the situation tends to get," he says hesitantly. "It's the law of attraction, honestly, a lot of that stuff. And the more you worry about it, and the more precautions you take, the worse it seems to be than it really is.

"But its pretty weird, and I don't want to come across like I'm preaching bad about that stuff, but it is pretty annoying. Once they know where you live – and there's so many of them now – they just wait there all day," says Efron, who recently purchased his first home, an unostentatious three-bedroom Hollywood one-storey house whose address is now known to every pap in town.

17 Again's director Burr Steers paints a more detailed picture: "Zac's fans knew pretty much every detail of our shooting schedule. Just getting him to the set each day involved a number of decoy vehicles and look-alikes. It was an incredible operation of almost presidential proportions, and at the centre of it all you have Zac, who managed to remain unbelievably normal." But Steers insists it was all worthwhile. "Put a camera in front of him, and he pretty much lights up. Getting Zac Efron to star in your film is the equivalent of winning the lottery."

If Efron is to be believed, his popularity wasn't always so: "Honestly, if anyone could see me in high school, I think they would just laugh because it's a complete 180 from what it is now," he says disarmingly.

"High school was great for a lot of reasons, and it sucked for a lot of reasons. I'm in a different place now where it seems like all the things that I used to worry about back then were so miniscule compared to things I worry about now."

Born Zachary David Alexander Efron in middle-class San Luis Obispo, 200 miles north of Los Angeles, he attended nearby Arroyo Grande High School. While his power-plant engineer father David and secretary mother Starla encouraged his academic studies, they couldn't ignore their eldest son's singing talent, enrolling him in vocal lessons which led to a small role in a local production of Gypsy which ran for four months. Going on to appear in stage productions of Peter Pan, Auntie Mame and The Little Shop of Horrors, he soon won guest spots in TV series ER, CSI: Miami and NCIS.

But he hit the jackpot when he was cast as the lead in Disney TV movie High School Musical in 2006. On his first audition, he would meet future girlfriend and co-star Vanessa Hudgens, and they have dated ever since then.

In 17 Again he plays a teenage father who abandons his dreams for family life in the suburbs – something young Efron has no plans of doing in real life: "I guess you take the necessary precautions. That was advice that was given to me very early on and I've followed it very well," he says teasingly.

"The very idea of kids at this point is frightening to me. Maybe its over-exposure at a young age to a lot of kids?! Right now, I think I'm honestly, deep-down, too selfish of a person. So I don't have that longing yet. I think eventually, maybe, it will come."

Does Efron believe in waiting for true love before having sex? "Sure, that's what my parents told me. That's what I believe; that's what I was brought up to believe. I think everyone thinks that at some point – its just how soon you change your own opinions, you know..."

Therefore it was with an open mind that he approached his sexy scenes with 37-year-old Leslie Mann: "I had no idea how it would turn out, but after five minutes of talking with Leslie, I have a crush on her. Sure, it was little awkward initially and I fluffed my lines a few times... now I'm blushing!"

It's a plot-line that is part Big and part The Graduate. Efron has no trouble anticipating a new Mrs Robinson-style following: "Absolutely," he grins. "I have no problem at all with that."

A few months ago Efron was spotted sitting alongside Leonardo DiCaprio at a Los Angeles Lakers game. "It was a complete fluke we sat next to each other, but it turned out to be the best thing that happened to me," he says. "Leo, for me, was the first time I ever recognised fame. I was in fifth grade when he was literally on every magazine cover for Titanic and all the girls had these Tigerbeat magazines and I'd say, 'Dude, what's so great about that kid?' I was jealous. I mean, you couldn't help but hate the guy. And now, to some degree, I've made it and I'm going through the same thing.

"But it was hard to talk to Leo that night because you're at a game and there's a million photographers and you're just trying to enjoy the game. He said a couple of small things but he suggested we talk outside of the game which I plan to take him up on. But it was a pretty weird encounter to meet this person whom I'd grown up hating, to now just completely loving his body of work. I mean, its pretty miraculous for him to have gone from that position to doing all the incredibly diverse films he does today. That's the kind of career I would like for myself."

Certainly he is heading in the right direction. Presently in pre-production on musical comedy Footloose, reprising Kevin Bacon's breakout role 25 years ago, later this year he will be seen starring opposite Claire Danes in Me and Orson Welles, based on Robert Kaplow's novel of the same name, and shot last year in the Isle of Man and London. He plays a teenager who becomes involved with an ambitious production assistant.

Precariously poised between youth and adulthood, he tells a story that demonstrates that curious divide between two worlds: "I was at the beach one day, building a sandcastle and generally just goofing off. Oh, this is embarrassing... So there I was, building a sandcastle, and I was digging and I got to a point where it was pretty cool, it was a pretty rad sandcastle and it was getting big, it was tall, well formed, holding up.

"And I had a big moat so the ocean wouldn't knock it down and then a young fan came up and I signed an autograph or something like that and she took a picture, after which she proceeded to jump directly onto my sandcastle and ruin it, and completely kill it and make explosion sounds and all this stuff and I thought that was pretty funny. I don't think she knew she was doing anything wrong.

"I don't know why that moment has stuck with me. I guess it has something to do with the fact that perhaps I'm too old to be building sandcastles today. But I can't help myself."

'17 Again' opens on 10 April