The moviemaker planned to give fans a behind-the-scenes look at the project, recorded at the New Temple Missionary Baptist Church in Los Angeles back in 1972, but he struggled to sync the sound and video footage and subsequently decided to dump the film, which he also titled Amazing Grace.

Pollack died in 2008, but producer Alan Elliott recently set about restoring the documentary and now it will debut at the Canadian film festival, which kicks off on 10 September (15).

Amazing Grace is just one of the many music-centric documentaries lined up for the 40th anniversary of the TIFF - Amy Berg's Janis Joplin film, Janis: Little Girl Blue, Barbara Kopple's Miss Sharon Jones! and Morgan Neville's The Music of Strangers, about the influence of cellist Yo-Yo Ma, are also set to be screened at the event.