More Hollywood heavyweights are joining the call for a lower rating on the teen-focused documentary "Bully".

The Weinstein Co, which is releasing the film March 30, said Tuesday that Johnny Depp, Meryl Streep and New Orleans Saints quarterback Drew Brees have signed on to support the film.

Lee Hirsch's documentary on bullying in American schools has been rated R, which restricts children under 17 from seeing it without an adult. The Motion Picture Association of America, which oversees movie ratings, cited language as the reason for the R rating.

Distributors appealed the decision, but it was upheld by the MPAA.

That prompted a Michigan teenager who was bullied in middle school to start an online petition calling for a lower rating for the film so more young people can see it. She met with MPAA officials last week and delivered the 200,000 signatures she collected, but the group declined to change the rating.

Katy Butler, a 17-year-old high school junior from Ann Arbor, now has nearly 300,000 signatures on her petition on Change.org. Among them is that of New York Sen. Kirsten Gillibrand, who tweeted Monday that she supports the teen's effort to lower the film's R rating to PG-13. Gerry Lopez, chief of AMC Theaters, also added his name to the petition, the Weinstein Co. said.

MPAA spokesman Howard Gantman did not address the possibility of a PG-13 for "Bully" in his response Tuesday to the growing call for a revision of its rating.

"We respect the viewpoints of members of Congress and the public and Hollywood celebrities who care deeply about an issue that is troubling our nation," he said in an email. "The MPAA shares the goal of shining a light on the problems caused by bullying, and we hope that this new film and the national discussion about it among educators, parents and students will help lead to ways to better ensure that kids feel safe and protected when they come to school."