* 30-minute documentary airs Sunday
* Movie seeks to help kids speak out
* Aimed at youths ages 8 to 13
By Susan Heavey
WASHINGTON, March 14 (Reuters) - President Barack Obama appears in an upcoming Cartoon Network documentary aimed at encouraging bullied children to speak up, and says that as the father of two young girls he is deeply concerned about the issue.
In an introduction to the 30-minute film, the president appeals to students, parents and teachers to take a stand on bullying.
"It's wrong, it's disruptive and we can all prevent it," said Obama, who hosted the first White House conference on bullying last year.
He stressed that he was speaking not only as the president but also as a father. "We've all got more work to do. Everyone has to take action against bullying."
The documentary, set to air nationally on Sunday, mixes stories from children who have been bullied with tips from those who have gotten past it. It includes interviews from celebrities, athletes and survivors who urge victims and bystanders to speak out.
Stuart Snyder, Cartoon Network president and chief operating officer, said the film is aimed at elementary and middle school students ages 8 to 13.
"Speaking up is the best way to bring an end to bullying," he told a crowd of about 400 students at a special screening of the movie at a middle school in Washington on Wednesday.
The broadcast comes ahead of the release of a longer documentary on the issue called "Bully." That movie has already generated controversy because of the Motion Picture Association of America's decision to give it a restrictive "R" rating despite objections from the filmmaker and others.
An "R" rating means those younger than 17 cannot be admitted to a film unless accompanied by a parent or guardian. That restriction will keep children who are the film's target audience from seeing it, critics of the rating say.
The Cartoon Network film features tennis star Venus Williams, NBA basketball all-star Chris Webber, several NASCAR race car drivers, and the hosts of the network's popular "Dude, What Would Happen" show.
It also features 14-year-old Alye Pollack, who fought back against bullying by filming a three-minute silent video and posting it on YouTube. Called "Words DO Hurt," she made it after she was bullied by a boy for two years. He saw it and apologized. Later, he even came to her defense when another child teased her.
"That was amazing. Now I'm kind of friends with him," she said of the apology.
The documentary airs Sunday at 5:30 p.m. EDT (2130 GMT) and again at 8 p.m. EDT (0001 GMT) on the Cartoon Network, which is owned by Turner Broadcasting System, Inc, a unit of Time Warner Inc.