Panic! at the Disco is the solo project of American musician Brendon Urie. It was originally a pop rock band from Las Vegas, Nevada, formed in 2004 by childhood friends Urie, Ryan Ross, Spencer Smith, and Brent Wilson. They recorded their first demos while they were in high school. Shortly after, the band recorded and released their debut studio album, A Fever You Can't Sweat Out (2005). Popularized by the second single, "I Write Sins Not Tragedies", the album was certified triple platinum in the US. In 2006, founding bassist Brent Wilson was fired from the band during an extensive world tour and subsequently replaced by Jon Walker. The band's second album, Pretty. Odd. (2008), was preceded by the single "Nine in the Afternoon". That album marked a significant departure from the sound of the band's debut. Ross and Walker formed a new band, the Young Veins, leaving Urie and Smith as the sole remaining members of Panic! at the Disco.
Continuing as a duo, Urie and Smith released a new single, "New Perspective", for the movie Jennifer's Body, and recruited bassist Dallon Weekes and guitarist Ian Crawford as touring musicians for live performances. Weekes was later inducted into the band's lineup as a full-time member in 2010. The band's third studio album, Vices & Virtues (2011), was recorded solely by Urie and Smith in 2010, produced by John Feldmann and Butch Walker. Crawford departed once the tour cycle for Vices & Virtues ended in 2012.
As a three-piece, Urie, Smith, and Weekes recorded and released the band's fourth studio album, Too Weird to Live, Too Rare to Die!, in 2013. Prior to the release of the album, Smith unofficially left the band due to health and drug-related issues, leaving Urie and Weekes as the remaining members. The duo recruited guitarist Kenneth Harris and drummer Dan Pawlovich as touring musicians for live performances.
In 2015, Smith officially left the band after not performing live with them since his departure in 2013. Shortly thereafter, Weekes reverted to being a touring member once again, resulting in Panic! becoming Urie's solo project. In April 2015, "Hallelujah" was released as the first single from Panic! at the Disco's fifth studio album, Death of a Bachelor (2016). In December 2017, Weekes officially announced his departure from the band. In March 2018, Panic! at the Disco released "Say Amen (Saturday Night)", the lead single from its sixth studio album, Pray for the Wicked (2018), which was released in June.