I’m thinking of songs like Mick Jagger singing backup on Carly Simon’s “You’re So Vain.” I’m not talking about one-off live performances where a star will make an appearance as a cameo. I also just mean singers, not musicians that played with the group like Glen Campbell with the Beach Boys. (Although he might have sung, I really don’t know.)
Also off of the top of my head:
The Beach Boys sang backup on a lot of Jan and Dean songs.
The Bee Gees provided backup on Samantha Sang’s “Emotion”. In fact, it was a long time before I came to learn that it wasn’t in fact a Bee Gee’s song. They also produced and sang on many of brother Andy’s hits.
The Jackson 5 sang on Stevie Wonder’s “You Ain’t Done Nothin’” I’m not sure who was more popular at the time but I’d say that the Jackson 5 went on to be more popular overall. Certainly Michael did.
Sting sang on Dire Straits “Money for Nothin’”. Again, I’m not sure who was more popular at the time but I know who went on to be the biggest.
Paul McCartney has done this many times, often uncredited or under a pseudonym:
“No Secrets” by Carly Simon
“Brave New World” by Steve Miller Band
“Walking Man” by James Taylor
…and numerous songs by Denny Laine and Ringo Star.
I suspect their fame is roughly equal but I really dig Joan Jett’s recent backup of Debbie Harry on “Doom or Destiny”.
Daryl Hall sung in the chorus of INXS’s “Original Sin.” INXS was in the studio and thought they needed a little more “punch” so the producer made a phone call and later that day Daryl Hall (at the height of his powers in 1983) walks through the door.
Kate Pierson of the B-52s sang backup on a number of R.E.M. songs (most famously, on “Shiny Happy People”). I don’t know if she was more famous than them, but she had been famous a lot longer.
Another case of a backup singer who was equally famous as the star is Tina Turner (and the Ikettes) singing (uncredited) backup on Frank Zappa’s “Overnite Sensation” album.
A UK comedy group called The Scaffold recorded a novelty song called “Lily the Pink,” which reached number 1 in the British charts in 1968. I don’t know that it was ever even released in the US, so most of you have probably never even heard it.
Backup singers included Graham Nash, Elton John (so young he was still going by Reg Dwight), and Tim Rice. Jack Bruce played bass.
It’s kind of a cute song.
Edited to add: One of the members of Scaffold was Mike McGear, aka Michael McCartney, Paul’s younger brother.
Emmylou Harris sang the duet “Oh My Sweet Carolina” with Ryan Adams on his solo debut album “Heartbreaker”. She definitely was much more famous than Adams at the time.
Huey Lewis and the News’s 1986 song *Hip to Be Square" has several members of the San Francisco 49ers as backup singers: quarterback Joe Montana, defensive back Ronnie Lott, wide recevier Dwight Clark, and linebacker Riki Ellison.
Not that Huey Lewis (the lead vocalist) was a small-time performer at that time, but Joe Montana might well have been more broadly famous.
Linda Ronstadt sang backup on Neil Young’sHeart of Gold, though it is arguable who is more famous. But in looking up that song title, I found this page:
The king of this has got to be Warren Zevon. His backup singers have included:
Don Henley
Stevie Nicks
Lindsay Buckingham
Glenn Frey
Bonnie Raitt
Linda Ronstadt
Jackson Browne
Bruce Springsteen
Dwight Yoakam
Emmylou Harris
Joe Walsh
Tom Petty
Michael Stipe
Neil Young
The Everly Brothers
Nick Kamen was a model who became famous in the UK in the mid 1980s after he appeared in a TV advert for Levis jeans. Madonna then supplied him with a track originally intended for her True Blue album and he had a 1986 global hit with Each Time You Break My Heart which Madonna wrote, produced and supplied background vocals on.
Sadly Nick died recently (4th May 2021) aged just 59 with cancer.
That’s interesting considering that I can think of exactly one Warren Zevon song. I’d heard “Lawyers, Guns, and Money” but I didn’t know that it was his.