To celebrate the incredibly prolific, influential and diverse body of work left behind by Prince, we will be exploring a different song of his each day for an entire year with the series 365 Prince Songs in a Year.

When Prince set about lining up guest artists for his 1999 Rave Un2 the Joy Fantastic LP, he offered to return the favor for his collaborators in exchange — an offer that No Doubt singer Gwen Stefani was more than happy to accept, leading to a day in the studio with a performer she'd long admired from afar.

As Stefani told Howard Stern years later, her Un2 enlistment wasn't the first time she'd come into contact with Prince. While stopping in Minneapolis on tour with No Doubt years before, she ended up spending some time with him — and receiving what she took as some slightly unusual advice.

"It was right around the time when Jennifer Lopez was putting out her stuff. 'Waiting for Tonight,' remember that song? I remember him, we all went out one night in a white limousine. He took us out, and he said, 'That's your competition,'" Stefani recalled. "I was like, 'What do you mean? That's nothing to do with me? That's Jennifer Lopez!' ... It was interesting. He just was up on everything."

Prince thought of Stefani while building the roster for the Un2 album, putting in a call she admitted was "super scary and intimidating" to receive. Still, she wasn't about to pass up the opportunity to work together, and she offered Prince a demo of her song "Waiting Room" in exchange for lending vocals to "So Far, So Pleased," a song Prince had set aside for his LP. The duo met in the studio for an eight-hour session that, according to Stefani, found him leading her through the recording, vocal part by vocal part.

"I went in the booth and I did not come out for, like, eight hours...I was so scared because I'm not even that good of a singer," argued Stefani. "Technically, as a singer, I kind of have my style or whatever, but it's not like I have a big range. "I can sing in tune, and I can hear notes, but he's just like a genius."

Stefani's surreal experience left her with one of the higher-profile guest credits on Rave Un2 the Joy Fantastic, and the other half of their collaboration surfaced two years later on No Doubt's Rock Steady LP, with Prince taking a co-writing and co-producing credit on the version of "Waiting Room" that was eventually released. Neither song was released as a single, but they reunited years later onstage to perform "So Far, So Pleased" — an experience Stefani laughed off as being less than her best live moment.

"I went and did it, and I was so nervous," Stefani told Stern. "You can look it up on YouTube — I was horrible. But I got to perform with him. I know he records that stuff and listens back, and he must have been like, 'What was I thinking?'"