Billy Howerdel is best known as member of A Perfect Circle. Previously Howerdel worked as sound engineer for several bands and artists such as Faith No More, David Bowie, Smashing Pumpkins, Guns'n'Roses, Nine Inch Nails and others. In 1992, Howerdel met Maynard James Keenan (frontman and lead singer of Tool) and it's from this meeting that rises the idea of making something together.