Norah Jones will appear on the forthcoming soundtrack for 'Wretches & Jabberers', a film about two men with autism.

Musician J. Ralph was so compelled by the script that he wrote 20 songs for it when he was initially set just to provide the film score, and asked artists such as Norah Jones to lend their voices to them.

Carly Simon, Scarlett Johannson, Ben Harper, Bob Weir and Vincent Gallo has also contributed to the soundtrack.

The documentary follows two men as they travel the world hoping to change attitudes to autism. It was directed by Oscar winner Gerardine Wurzburg and will be released this April, National Autism Awareness Month. 

Watch the official trailer for 'Wretches and Jabberers' below: