A Perfect Circle was formed in 1999 as a rock super group with members from Tool (Maynard James Keenan), Nine Inch Nails, and The Smashing Pumpkins (Billy Howerdel) to name a few. Though the lineup changed throughout the years, Keenan and Howerdel have been the two constant members.

Originally, Howerdel wanted a female vocalist for the group but after Keenan said he could hear himself singing the songs Howerdel wrote when he played them for him, he reconsidered. Who would turn down Maynard James Keenan? Not me.

The group has three albums to date, Mer de Noms, Thirteenth Step, and eMOTIVe. The band went into a hiatus in 2004 and claimed in 2010 that Keenan and Howerdel would be working on new music for the group but no word has come out on the progress or lack there of, of any songs to date.