Author J.K. Rowling (2nd R), producer David Heyman (L), actress Emma Watson (2nd L) and actor Rupert Grint pose after Rowling and Heyman received an award for outstanding contribution to British cinema at the British Academy of Film and Television Arts (BAFTA) award ceremony at the Royal Opera House in London February 13, 2011.[Photo/Agencies]

LOS ANGELES - If the young cast of the "Harry Potter" films received report cards for their school days at Hogwarts, they'd all probably earn the notation, "plays well with others."

Cast as impressionable children in Hollywood's biggest fantasy franchise, Daniel Radcliffe, Emma Watson, Rupert Grint and their many young co-stars have maneuvered through 11 years of fame — and the temptations it brings — without any whispers of Lindsay Lohan-style meltdowns that can derail child actors.

They've grown up smart, humble, polite and professional, eager to balance modest private lives with productive acting careers rather than leap into the party-till-dawn celebrity lifestyle.

The actors and the headmasters of the Warner Bros. franchise say it wasn't magic that kept the kids on their best behavior. It was the luck of the draw when the youngsters were first cast, good parenting, mindful shepherding that resembled the rigors and care of the finest boarding schools, and a sheltered workplace outside of London, far from Hollywood's madding crowds.

"It's very different doing it in England," said Radcliffe, who was 11 when cast in the title role as the boy wizard for 2001's "Harry Potter and the Sorcerer's Stone" and turns 22 the week after the mid-July debut of the final film, "Harry Potter and the Deathly Hallows: Part 2."

"In America, you're treated as an actor first and a kid second. Here, you're very much treated as a kid first and an actor second. In fact, you're not really treated as an actor. You're treated as a kid on a film set, which is how it should be, because that's all you are that point. No one's an actor at 12."

And with the performers so young, their parents were instrumental in steering the children through busy working lives and the madness of instant celebrity.

"We couldn't have done it without the family support that's kept all three of them and the supporting cast all lovely, lovely people," said David Barron, a producer on most of the "Harry Potter" films. "They've got very strong families who kept them really strongly grounded."

With tens of millions of "Harry Potter" fans to please and billions of dollars at stake, Warner Bros. went to great lengths to protect and nurture the stars through eight films and a decade of hard work.

Sets to create author J.K. Rowling's Hogwarts School of Witchcraft and Wizardry and other Potter locations were built at Leavesden Studios northwest of London, giving the filmmakers a controlled environment where they could work and essentially help raise their young charges.

"It's been a bit of a bubble, and it's been very self-contained, and I think we just have good people around us," said Watson, who was 10 when cast as Hermione Granger and now is 21. "We've just been lucky that we haven't been exploited in any way."

Radcliffe, Watson, Grint and such co-stars as Tom Felton, Bonnie Wright, Evanna Lynch and Matthew Lewis had tutors on set, along with armies of studio publicists to help coach them through the media circus of almost-annual premieres and press junkets to promote each film.

The filmmakers say Leavesden became a kind of Hogwarts boarding school for the cast.

"It was a place that was just us, nobody else," said David Heyman, a producer on all of the "Harry Potter" films. "That has enabled us to sort of cocoon ourselves in an environment, in a way, that I think is a supportive and a safe one."

"To have children grow up in that kind of maelstrom of affection and general applause for everything they do, it's not normal, and you can imagine it very easily could have ended in somebody going off the rails somewhere," producer Barron said.

"But they were never put under the microscope of the outside world whilst they were working. ... If ever they got a bit bumptious when they were younger, the bubble was very quickly burst by someone or other on the crew, who just said, 'Oh, yeah? Come on.'"

The actors developed strong work ethics, and the filmmakers saw traits in their stars that mirrored those of the characters.

Like Harry, Radcliffe assumed a solicitous leadership role, sort of a goodwill ambassador on set. Like Hermione, Watson was studious, hurling herself into her education. Like Ron Weasley, Grint had a playful humor and the support of a large family.

"You felt people are just kind of waiting for us to fall into that stereotype of, I suppose, child actors," said Grint, who started on "Potter" at age 11 and turns 23 a month after the final film opens. "But I've always been quite busy. Never really had much time to go too crazy. I come from a big family, as well, and that always helps you to know who you are."

Director David Yates, who made the final four "Harry Potter" films, said he wondered a few years back whether some of his stars might turn into a handful as they reached the rebellious late-teen years.

"Because, they have every right to kind of get angry or frustrated," Yates said. "They carry a lot of responsibility. They're under tremendous pressure. They have enormous temptations. The world is at their feet. They get paid enormous amounts of money. But they haven't gone over the edge, and I think it's the people around them. I think there's something ingrained with them. It's their family."

Many child actors have trouble landing more adult roles once they outgrow their cute and cuddly phase and can get sidetracked into drugs or alcohol, such as Lohan and others before her, including Danny Bonaduce, Corey Feldman and Macauley Culkin.

So far, the key "Potter" stars have remained focused. Radcliffe has done Broadway with "Equus" and "How to Succeed in Business Without Really Trying," and stars in the upcoming big-screen thriller "The Woman in Black." Watson is studying at Brown University and has a role in the upcoming Marilyn Monroe drama "My Week With Marilyn." Grint did a couple of independent movies in between "Potter" films and stars in the upcoming war saga "Comrade."

Radcliffe recalls endless questions over the past decade as people asked him, "Aren't you scared about what's happened to these other child stars?"

"Having to answer that so many times made me go, 'Jesus, if you're asking this so many times, now if I do go off the deep end, I'm just never, ever going to hear the end of that,'" he said. "By now, I do view it as sort of a personal mission that I have. If all of us in this big franchise can then go off and have successful, balanced lives, careers, whatever, I'm hoping that I paved the way for the next generation of child stars in not having to answer those questions."