VIDEO : Sundance: Diane Warren Talks Collaborating With Lady Gaga for 'The Hunting Ground' Doc

The most talked about song at the Sundance Film Festival is one that very few people have heard: Lady Gaga's "Til It Happens To You" from The Hunting Ground. Diane Warren, Oscar-nominated this year for "Grateful" from Beyond the Lights, wrote "Til It Happens To You" after being shown scenes almost a year ago. She took the song to Gaga ? sharing a writing credit with Warren ? who quickly recorded it. The song appears in the body of the film to underscore the pain of a survivor of sexual assault.