Spike Lee uses unreleased Prince recording in his new movie

Slowly, very slowly, music is finally coming out of Prince's mysterious vault.

Celebrated filmmaker Spike Lee is using Prince's recording of the spiritual "Mary Don't You Weep" in his new movie "BlacKkKlansman," Rolling Stone reports.

Lee had invited Troy Carter, entertainment adviser to the Prince estate, to a screening of the movie. The director said he needed a song to play during the closing credits. Carter said he had the tune, a version of the spiritual that Prince had recorded in the mid-1980s.

"Prince wanted me to have that song for the film, I believe," Lee told Rolling Stone. "This cassette is in the back of the vaults, in Paisley Park. And all of a sudden, it's discovered? Nah-ah. That ain't an accident."

The movie, which tells the true story of a black cop who infiltrated the Ku Klux Klan in the 1970s, is scheduled to open on Aug. 10. The film won the Grand Prix prize at the Cannes Film Festival in May.

Working on behalf of the estate, archivist Michael Howe has been cataloging material found in the vault. The contents of the vaunted storage room at Paisley Park have been shipped to the Iron Mountain facility in the Los Angeles area.

One other item from the vault, Prince's version of "Nothing Compares 2 U," has been released, as a single in April.