Having worked together on Prince’s “Money Don’t Matter 2Night” music video amongst other projects, Prince and Spike Lee were friends and mutual fans for decades. The director even threw a spontaneous block party in the hours after Prince died of a drug overdose in 2016, making the event a memorial celebration that takes place annually near Lee’s Brooklyn offices. The singer’s close confidant is continuing to keep his music legacy alive this time around with a rare musical feature in the upcoming drama-crime film BlacKkKlansman. The film is based on the true story of an African-American police officer named Ron Stallworth who infiltrated the Ku Klux Klan in Colorado during the 1970s. Lee spoke to Rolling Stone about how he acquired a rare Prince song to play over the film’s end credits.

“I’ve become very close with Troy Carter [the ex-Spotify executive who  is also the entertainment advisor to the Prince estate, and oversaw sponsorship of Lee’s 2017 Prince memorial celebration]. So I invited Troy to a private screening. And after, he said, ‘Spike, I got the song.’ And that was ‘Mary Don’t You Weep,’ which had been recorded on cassette in the mid-‘80s…Prince wanted me to have that song, I don’t care what nobody says. My brother Prince wanted me to have that song. For this film. There’s no other explanation to me. This cassette is in the back of the vaults. In Paisley Park. And all of a sudden, out of nowhere, it’s discovered? Nah-ah. That ain’t an accident!”

Spike Lee also discussed the importance of the scene that the song will play over, which involves footage from the white supremacist rally that took place in Charlottesville, Virginia. He shared that he first asked Ms. Susan Bro for permission to use the footage in the film, as her daughter Heather Heyer was murdered by an American terrorist who drove a car down a crowded street.

“Mrs. Bro no longer has a daughter because an American terrorist drove that car down that crowded street. And even people who know that thing is coming, when they see it, it’s like, very quiet. People sit there and listen to Prince singing a Negro spiritual, ‘Mary Don’t You Weep.’”