PARK CITY, Utah (Reuters) - Since the 1994 box office hit "Hoop Dreams," documentaries have come a long way from basic reporting with expert witnesses to fictional-style storytelling more like feature films in movies such as 2005's "Murderball."
But this year at the Sundance Film Festival, which kicked into high-gear this weekend and has long championed non-fiction film as an art form, something new appears to be afoot -- the rise of the celebrity documentary, or "star doc."
With big-names backers like Ben Affleck with "Reporter" and Chris Rock with "Good Hair," this year's Sundance is filled with documentaries that have gone Hollywood.
The reasons stars ventured into documentary filmmaking varies, but they say they all share a common desire to tell real-life stories in ways that feature films can't.
"There's an axiom, 'if you put it in a movie, no one will believe it,'" Affleck told Reuters. "There's a power to seeing something that you know is true, and that lends a kind of urgency" to the subject.
Sundance is the top gathering for independent films and throughout its 25-year history, founder Robert Redford has pushed festival programmers to reach out and find the best documentaries from around the world.
"Hoop Dreams," about the struggles of young basketball stars, was among the first films Sundance championed that proved audiences will turn out for documentaries in theaters, he told reporters at a news conference last week.
Perhaps Sundance's biggest success was premiering the 2006 environmental doc, "An Inconvenient Truth," which earned the Oscar for best documentary and returned former vice president Al Gore to the media spotlight.
"Reporter" follows Pulitzer Prize-winning journalist Nicholas Kristof to the eastern Congo where armed conflict has led to the death of more than 5 million people in the past decade, according to the film directed by Eric Daniel Metzgar.
But in focusing on Kristof, "Reporter" also talks about the rapidly changing world of journalism and ponders the question of whether in the blog-infused Internet, stories requiring a deep understanding of a subject and expensive journeys to far-flung edges of the world will remain viable for reporters.
Metzgar welcomed Affleck as executive producer, saying his celebrity obviously brought attention to the story, but also that Affleck knew as much, if not more, about the plight of eastern Congo than he.
"It helped inform us about how to tell the story," Metzgar said. "He's using his own voice and own spotlight to bring attention to the Congo, and that is admirable. And he's successful, and we wanted to be part of that."
"Good Hair," which was directed by Jeff Stilson and co-written by Rock, is far different, but no less serious or informative. In it, black comedian Rock delves into the culture of African Americans and their hair.
Rock travels to hair salons, styling contests and cosmetic product laboratories to explore how hair has impacted the self-esteem and even sexual relations of black people.
"You come out learning something and hopefully having a good time along way. It's pretty funny," said Rock.
They aren't the only names with documentaries at Sundance. Director James Toback premiered "Tyson" to humanize the much-maligned former championship boxer, Mike Tyson.
Spike Lee, who dipped into the world of documentaries with Hurricane Katrina tale "When the Levees Broke," made his Sundance debut with "Passing Strange" about the rise-and-fall of a Broadway musical that looks at the life of a black man.
"Several times I saw it when it went to Broadway," he told Reuters. "I'm just very happy we were able to preserve the play because when most plays go down, they are lost forever."
Editing by Anthony Boadle