A documentary about Kurt Cobain is being made.
Brett told the new York Post newspaper: ''Courtney is the one that brought me into this.
''We've been trying to find the right time to put this film together and the time is now.''
Brett - who directed a recent film about The Rolling Stones, 'Crossfire Hurricane' - also explained how the movie will not be a straight documentary about the singer and guitarist, who committed suicide in 1994, but made in an ''autobiographical'' way.
He added: ''Kurt was not only an amazing songwriter and musician, he was an incredible artist and filmmaker.
''So we are going to do the movie sort of like a third-person autobiography - as if Kurt was around and making a film about his life.''
Last month Sam Lutfi, who claimed to be Courtney's co-manager said she was working on a script for a musical or a film about her life with Kurt, but she was quick to dismiss these rumours.
She said: ''There will be no musical. Sometimes it's best just to leave things alone.''
Many films have been made about and inspired by Kurt since his death, including 'Last Days' by Gus van Sant, a lose fictionalisation based on what the rocker's final days may have been like, and documentary 'Kurt and Courtney' by Nick Broomfield, which explored the theory Kurt could actually have been murdered.
Brett is planning his documentary for release in 2014.