Once an artist is established as the primary force in a successful band, it's pretty rare to see them join another band as a sort of background figure, but these six artists did exactly that. Here are six artists who became sidemen in other bands.

1. Johnny Marr

For the five years that the Smiths existed during the '80s, Johnny Marr was one of the most important songwriters and guitarists on the planet. After he left the band in 1987, however, he opted to not start another band or pursue a solo career like Morrissey. Instead, he joined the line-ups of already established bands such as the Pretenders, Talking Heads, and most unexpectedly, Modest Mouse. From 2006 to 2009, Marr was an official member of Modest Mouse, playing on the album We Were Dead Before the Ship Even Sank before leaving to join another band, the Cribs.

2. David Bowie

David Bowie and Iggy Pop became friends in the early '70s when Bowie produced the Stooges third album Raw Power, but after the Stooges broke up, Bowie and Pop continued to collaborate. Bowie produced and co-wrote Iggy Pop's first two solo albums The Idiot and Lust for Life, and even played keyboards in Pop's band on tour, which is high up on my list of shows I wish I was alive to have seen.

3. Pat Smear

When it comes to American punk timelines, Nirvana and the Germs don't really overlap. The Germs was one of the original bands of the Los Angeles punk scene back in 1977, while Nirvana formed in 1987, seven years after the Germs broke up. However, Germs guitarist and songwriter Pat Smear reached his biggest audience when he joined Nirvana in 1993 as a touring guitarist, eventually playing on the MTV Unplugged album. After Nirvana ended, Smear would stay in the mainstream as a member of Foo Fighters with Dave Grohl.

4. J. Mascis

J. Mascis is one of the most acclaimed guitarists in alt-rock history, but guitar wasn't even his first instrument. Mascis started out as a drummer in the hardcore band Deep Wound, but became known as a guitar hero when he started Dinosaur Jr. Mascis eventually went back behind the drum kit in 2005 when he started a stoner metal band called Witch, leaving the guitars and vocals to frontman Kyle Thomas.

5. Robert Smith

By 1983, the Cure was already an established act, with mainstream success and four albums to its name, but frontman Robert Smith took a break from the Cure that year to play with Siouxsie and the Banshees when they had trouble finding a guitarist. Smith played guitar on one album for the Banshees, 1984's Hyaena, before returning to the Cure.

6. Alex Chilton

Alex Chilton had a bizarre career trajectory during the '60s and '70s. He achieved mainstream success as a teenager with the Box Tops, went on to record three incredible but commercially unsuccessful albums with Big Star, integrated himself into the punk scene at CBGB's, and in 1979, joined the psychobilly band Tav Falco's Panther Burns as a guitarist. Much like Stevie Wonder and Scott Walker, Chilton was trying his hardest to progress beyond the successes of his teen years.

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