TORONTO -- When "The Perks of Being a Wallflower" got a standing ovation at its Toronto International Film Festival premiere this past week, writer-director Stephen Chbosky felt like he was witnessing a pivotal moment in star Emma Watson's life.
"I know what it meant to her, to have that kind of acceptance for another role other than her beloved part. It meant the world," he said of the 22-year-old British actress, who's known worldwide for playing Hermione Granger in the "Harry Potter" franchise.
"I know for her it's just a great letting go and being seen and accepted for something else -- and it's only the beginning. She's going to do so many great parts we're going to lose count."
Watson, who plays free-spirited teen Sam in the coming-of-age drama that Chbosky adapted from his own novel, was one of several young stars who shed their most memorable moulds with more adult-oriented projects at this year's festival.
Kristen Stewart, 22, stepped outside of her beloved Bella Swan "Twilight" character with the sultry role of Marylou in "On the Road," directed by Walter Salles and based on Jack Kerouac's cult classic.
Of course, the actress couldn't escape "Twilight" talk while at the fest (it was her first official public appearance since news broke that she had cheated on her franchise co-star/boyfriend Robert Pattinson with married director Rupert Sanders).
But Stewart embraced the "Twilight" fan base, saying she hoped those who read the Stephenie Meyer books might also pick up "On the Road," which was her favourite book in her freshman year of high school.
"One thing I do know about 'Twilight' fans is they've got a lot of passion, a lot of heart," Stewart said in an interview.
"The idea that we could have anything to do with even one person reading 'On the Road' that wouldn't have read it is mind-blowingly cool to us."
Other former child actors shedding their fresh-faced images at the Toronto festival included former "High School Musical" Disney star Zac Efron, who was featured in two weighty dramas.
In Lee Daniels' "The Paperboy," Efron stars as a budding journalist who falls for Nicole Kidman's bombshell character and has several scenes in just his underwear.
And in "At Any Price," from arthouse director Ramin Bahrani, Efron plays a spoiled rich kid who clashes with his father (Dennis Quaid) to pursue his dreams.
"It'd be so easy for him to do these heart-throb roles, he could have a Tom Cruise career just like that, you know," Quaid said of the 24-year-old Efron.
"But he's really kind of going about it more like Johnny Depp did, taking these smaller films that are a little bit more interesting I think right now, and I think it's going to serve him well as far as his overall career."
Efron admitted he was apprehensive about losing his established audience with his role in "At Any Price."
"But I think usually in life when you have those feelings that's a sign you're going in the right direction," he said in an interview.
"And you have to confront your fears head-on, and it's safe to say that on the outside, doing this movie scared me, to a degree. I always have a fear of the unknown, fear of something I haven't tried before or something that's out of my wheelhouse. But in the past when I've gone for those things and pushed harder than ever to make them, to follow through with those things it's been the right choice.
"And I look to my elders and what they would have done and the men that I appreciate and respect would have done."
Meanwhile, fellow Disney graduates Selena Gomez and Vanessa Hudgens were at the fest with Harmony Korine's "Spring Breakers," which also stars Ashley Benson of "Pretty Little Liars" teen soap fame.
Gomez's clean-cut character -- not-so-subtly named Faith -- is the naive, conscientious voice of reason amid the film's quartet of empty-eyed partiers. But the pop star spends most of her screen-time grinding on the dance floor, tipping back red cups and puffing on bongs, while her similarly bikini-clad friends get up to worse.
"The biggest challenge for me is that I do have a younger generation of fans that support me and that mean a lot to me," Gomez, 20, said at a festival news conference.
"Plus, I think it's hard for people to take me seriously in that way because of the brand that I've been given, which I'm grateful for, but you know ... people obviously (put) you in this little box."
When asked what she would tell her young fans curious about the risque film, Gomez replied: "Don't see it."
Mary Elizabeth Winstead, 27-year-old star of the festival hit "Smashed," admitted young actors are afraid to say no, even if money isn't an issue.
"You never know if it's going to come back, it's scary to turn anything down," she said in an interview.
"I think every actor has those insecurities; no matter how big you get you're worried that the next job is never going to come, so it can be hard to take that leap, for sure."
It can be even harder if you're a female actress trying to make the transition into more adult rules, noted Chbosky.
"Especially for girls, it can often be very difficult because people see you as that child and they feel attached to you, and then you become this young woman," he said. "And so I felt fiercely protective of Emma as a person, because I knew what this role meant to her.
"But then as an artist -- because again, I think she's phenomenal -- I had to really do my job, because if I didn't then I would hurt a brilliant burgeoning young career, and I would never have forgiven myself, and it made me better because I was never going to let that girl down.
"Everyone knows the pressure on young starlets, child actors, to suddenly become sexualized -- the pressure is so extreme, and what I so admire about Emma is that she didn't go to that place."
The Toronto film festival wraps on Sunday.
