Zwan was an American alternative rock supergroup formed in 2001 by lead guitarist and singer Billy Corgan and drummer Jimmy Chamberlin, from The Smashing Pumpkins. Other members included bassist Paz Lenchantin of A Perfect Circle, and guitarists David Pajo of Slint, and Matt Sweeney. The band released only one album, Mary Star of the Sea (2003), before breaking up acrimoniously that year during their world tour to promote the album.

Following the disbanding, Corgan released a solo album, TheFutureEmbrace before reforming the Smashing Pumpkins in 2005, with Chamberlin joining in 2006. Despite allusions to multiple albums' worth of material written by band members, no further material has surfaced beyond their only studio album, and none of the material has been revisited in performances by any of the members outside of a brief 2017 tour by Corgan. In his 2019 solo shows, Corgan played "Honestly" and "Endless Summer" on several dates of his European summer tour.