Tomorrow marks the 40th anniversary of Prince’s sophomore album, the self-titled LP that he released when he was just 21. Prince wasn’t a fully formed genre-melting genius at the time, but he was well on his way, cranking out amazingly springy and sexy synth-funk jams with astonishing speed. At the time, the big song from the album was “I Wanna Be Your Lover,” the single that he took to #11 in the early days of 1980. (Prince wouldn’t score his first top-10 single until “Little Red Corvette” in 1983.) But years later, someone else took another one of those self-titled album songs and made a huge hit out of it.

Prince scored plenty of hits with Prince songs in the ’80s. But so did plenty of other people — Cyndi Lauper, the Bangles, Martika. In 1984, Chaka Khan recorded a version of “I Feel For You,” a slinky jam from Prince’s self-titled album, that she took to #3. Chaka Khan transformed the song into machine-tooled digital club music. Her version featured rapping from the Furious Five’s Melle Mel and harmonica from Stevie Wonder, and it also sampled Wonder’s “Fingertips (Pt. II).” But it was still very recognizably a Prince song. And today, we get to hear that song’s origins.

Right now, after Prince’s death, the man’s estate is busy monetizing the many, many unheard recordings that he left behind. Prince probably wouldn’t have wanted this, but it means we get to hear these holy-grail pop moments, so you can do your own ethical calculus. This past summer, we got the album Originals, featuring Prince’s original demos of songs that went to other artists. There’s also an expanded edition of 1999 on the way. And today, to mark the 40th anniversary of that self-titled LP, we get to hear the original acoustic demo of “I Feel For You.” (You can tell it’s early Prince because it’s not called “I Feel 4 U.”)

Prince recorded the solo-acoustic “I Feel For You” demo early in 1979, when he was just 20. And yet there’s nothing rough about it. Prince’s guitar virtuosity, his liquid falsetto, and his rhythmic sense of command are all fully evident. In a press release, Prince archivist Michael Howe, says, ““I was blown away. Here is 20-year-old Prince thinking aloud, feeling his way through the song. You hear his incredible talent shining through on acoustic guitar, which is not something he typically showcased, and his guide vocal is astonishingly great.”

The Prince estate is putting out a 7″ with the “I Feel For You” demo and the fully-produced version of the song, and you can stream it below. While you’re at it, you can also watch Chaka Khan’s video for her 1984 version.

You can buy the “I Feel For You” 7″ here.