The Head Cat was a side project that allowed Lemmy to indulge his passion for rockabilly and first-era rock. The Head Cat featured Lemmy on bass, guitars, and vocals; Slim Jim Phantom of the Stray Cats on drums and vocals; and Danny B. Harvey of the Rockats and the Lonesome Spurs on guitar, bass, and keys. The trio came together when Lemmy was invited to contribute guitar and vocals for the 2000 album A Special Tribute to Elvis by Phantom and Harvey's group the Swing Cats. After cutting a version of "Good Rockin' Tonight," Lemmy picked up a guitar and began jamming on some classic Eddie Cochran tunes. Phantom and Harvey quickly joined in, and the three felt the chemistry was right and they should cut an album of their own.

In 2000, the trio recorded Lemmy, Slim Jim & Danny B, which was released by the German label Steamhammer; it was reissued in a different sequence and with new artwork in 2006 by Cleopatra Records under the title Fool's Paradise. The band played occasional live dates when their schedules permitted, and a 2004 show in Los Angeles was released in a special DVD/LP package, 2006's Rockin' the Cat Club: Live from the Sunset Strip. In 2011, the Head Cat brought out a second studio album, Walk the Walk...Talk the Talk. While the debut album consisted entirely of vintage rock & roll covers, Walk the Walk featured a pair of original numbers along with ten rockabilly, blues, and country chestnuts.

The Head Cat continued to play occasional club and festival dates until early 2015, when Lemmy's failing health began to interfere with his performance schedule. The Head Cat were scheduled to perform as part of a Lemmy birthday show on December 13, 2015, but Kilmister was too ill to participate. He died on December 28, ending the trio's memorable run. ~ Mark Deming