A Perfect Circle is an American rock supergroup formed in 1999 by guitarist Billy Howerdel and Tool vocalist Maynard James Keenan. The original incarnation of the band also included Paz Lenchantin on bass, Troy Van Leeuwen on guitar, and Tim Alexander on drums, with Josh Freese as the primary drummer after the band`s initial round of touring prior to their first album. The latest lineup features Puscifer bassist Matt McJunkins; former The Smashing Pumpkins guitarist James Iha; and Puscifer and Ashes Divide touring drummer, Jeff Friedl. Despite having a varied cast since inception, the stylistic content of the songs has remained consistent with Howerdel as composer, and Keenan penning the lyrics and melodies.

A Perfect Circle has released three albums: their debut Mer de Noms in 2000, a follow up, Thirteenth Step in 2003, and an album of cover songs titled Emotive in 2004. Shortly after Emotive`s release, the band went into hiatus while members focused on other projects, the most notably being Keenan`s work with Tool and Puscifer, and Howerdel`s putting out a solo album, Keep Telling Myself It`s Alright, under the moniker Ashes Divide.

In late 2008, Keenan and Howerdel announced the band would reform, though the band`s activity would ultimately be sporadic in the coming years. The band toured in 2011 and played some live shows in 2013 to promote the release of a live album, A Perfect Circle Live: Featuring Stone and Echo, and a greatest hits album, Three Sixty. Work on new material has been alluded to by members since 2008, though progress was slow due to Keenan`s other commitments and uncertainty in the direction of the releases. The only new studio material released since the band`s hiatus was the single "By and Down" in 2013. In 2017, the band signed a new record contract to release a fourth studio album through BMG Rights Management, and announced a North America tour starting in May 2017 as well.