Often decried for its heavy-handed proselytizing, 2001's The Rainbow Children nevertheless featured some of Prince's most interesting late-period music – and drummer John Blackwell Jr. played a huge role in that.

The songs, on their face, are drawn from Prince's typical bag of offbeat combinations – psychedelic fusion, hard-rock R&B, soul and jazz – but they're presented in consistently inventive, deeply involving ways. (Tellingly, The Rainbow Children would mark the first new album credited to Prince, rather than an unpronounceable symbol, since 1994.) Blackwell, who played with Prince off and on for more than a decade, served as the beating heart of this underrated era.

That started here, with Blackwell's first-ever Prince collaboration. He was, as always, this force of nature, a performer who pushed Prince into new musical territories even while being steadfastly true to himself. They'd established this relationship dynamic from the first, when an oblivious Blackwell blew away Prince during an earlier gig with Patti LaBelle.

"I was so into what I was doing with Patti on stage, I kind of blocked everybody out – anybody who was around the stage," the late Blackwell told LiveDaily's Don Zulaica in 2002. "I was aware that Prince could have been in the building that night, but being in the zone I was in, I didn't let that distract me. Because if I had let that get to me, I probably wouldn't be on Prince's gig right now. I would have tried to showboat or whatever – and Prince would have known that in a second."

Instead, Prince saw a fearless, jazz-infused performer living out his dream, and making good on his birthright. After all, Blackwell – a South Carolina native who had already performed with Billy Eckstine and Cameo after attending Boston's Berklee College of Music – was himself the son of a drummer known as "Pocket Man."

He'd help Prince rediscover a more organic sound, appearing on 2003's Xpectation and the Grammy-nominated N.E.W.S., as well as 2004's Musicology and a number of tours as a member of the New Power Generation. He later played with Justin Timberlake, Maze featuring Frankie Beverly, D'Angelo and Bootsy Collins, before being stricken with debilitating brain tumors.

Blackwell remained upbeat after his diagnosis, which arrived just as he was set to play a solo gig at the Blue Note Tokyo jazz venue. He eventually lost the use of an arm and a leg. Blackwell was already mourning Prince, who'd recently died after an accidental overdose, but he wasn't ready to join his old boss in what would have been the funkiest of after-life bands.

"I can hear Prince now say, 'I'll just call John,'" Blackwell told South Carolina's WLTX in 2016, laughing. "No, you ain't! I don't want to do that gig. Not yet."

In the end, their chance meeting had grown into a father/son-type relationship, one that emerged from this instant musical connection. Blackwell unknowingly produced the music for "Everywhere" while getting set for their very first collaboration.

"I was just checking my drums, and the engineer was trying to get a good miking of everything at that moment," Blackwell told Zulaica. "And they said, 'We've got everything miked. Now play everything so we can get a good mix.' So, I'm just messing around playing some beats, and I did a fast, Latin-type of beat that you would hear Dennis Chambers or Billy Cobham play. They were like, 'Man. Keep that going.'"

By the morning, something magical had happened. "I came into the studio the next day and it's a song," Blackwell marveled. "It's got vocals in the background, and it was beautiful. I had no idea what it was going to be."

Blackwell was just 43 when he died.

Prince Year by Year: 1977-2016 Photographs

More From Ultimate Prince