90s at 9 Don't know Ozzy? Don't let that stop you

Mike Muir envisioned Ozzy singing the chorus on this song, but didn't know Ozzy. Happenstance brought them together and the rest is history.

"Therapy" by Infectious Grooves was written by lead singer Mike Muir and bass player Robert Trujillo and included on their debut album The Plague That Makes Your Booty Move...the Infectious Grooves.  It got airplay on MTV's Headbanger's Ball. 

The song features Ozzy on the chorus and here's the story of how that came about.

In an interview with Songfacts, Muir commented on working with Osbourne:

When we were doing the record and first started recording it, the producer said, "What do you want to do on the chorus?" I said, "I actually think it would be really cool if Ozzy sang on it." And they're like, "Oh, give him a call." I'm like, "Dude, I don't know Ozzy." [...] And then two days later, I came in the studio, and he goes, "Guess who just came in the studio next door?" And I'm like, "Who?" And he goes, "Ozzy." I'm like, "You serious?" And he goes, "Yeah, go talk to him." I'm going, "I'm not going to talk to him!" We went to lunch and we came back later and there he was in there. He goes, "You have a song you want me to do?" I'm like, "Uhhhhddduuuhhh." And he put the song on, and he's like, "I want to do it! I want to do it!" And it was really cool. So it's funny, 'cause after we did it at least like once or twice a day and in the evening, we hear this little knock or something and look and he'd be poking his head through and he's like, "'Scuse me, will you play that song for me again?" And he'd get in there and listen and start jumping and he goes, "I love it! I love it!" (laughing)

Ozzy was so impressed with Infectious Grooves he brought them along on his No More Tears Tour in 1991 and in 1999 bass player Robert Trujillo joined Ozzy's band before leaving to play with Metallica in 2003.
Infectious Grooves "Therapy" 1991