Panic!
 at the Disco is an American rock band from Las Vegas, Nevada, formed in 2004 and featuring the current lineup of lead vocalist Brendon Urie, accompanied on tour by bassist Dallon Weekes, lead guitarist Kenneth Harris, and drummer Dan Pawlovich.
 The group was originally formed by former members Spencer Smith and Ryan Ross.
 The band has gone through multiple line-up changes in their career spanning five albums.
 There have been six official members of Panic!
 at the Disco, six touring members and twenty-six session members.
Death of a Bachelor is the fifth studio album by American rock band Panic!
 at the Disco, released January 15, 2016 on Fueled by Ramen and DCD2.
 It is the follow-up to the band's fourth studio album, "Too Weird to Live, Too Rare to Die!
" (2013), with the entire album written and recorded by lead vocalist/multi-instrumentalist Brendon Urie, among external writers.
 It is the band's first album to not feature drummer Spencer Smith and also follows bassist Dallon Weekes' departure from the official line-up, subsequently becoming a touring member once again.
"New Perspective" is a song by American rock band Panic!
 at the Disco, released on July 28, 2009 as a single promoting the film "Jennifer's Body".
 Vocalist Brendon Urie began writing the song two years prior to its recording regarding a lucid dream he had.
 The song was completed in the summer of 2009, and was co-written by producer John Feldmann.
 "New Perspective" was Panic!
 at the Disco's first single in aftermath of the departure of guitarist Ryan Ross and bassist Jon Walker, both of whom had no involvement in the track.
Panic!
 at the Disco is an American rock band from Las Vegas, Nevada, formed in 2004 and featuring the current lineup of vocalist Brendon Urie, accompanied on tour by bassist Dallon Weekes, guitarist Kenneth Harris and drummer Dan Pawlovich.
 Founded by childhood friends Ryan Ross, Spencer Smith, Brent Wilson and Urie, Panic!
 at the Disco recorded its first demos while its members were in high school.
 Shortly after, the band recorded and released its 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 double 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.
Dallon James Weekes (born May 4, 1981) is an American singer, songwriter, and musician.
 He is best known as a long-time contributor for Panic!
 at the Disco.
 Since 2009, Weekes has performed in the band as a bassist, keyboardist, backing vocalist, and songwriter.
 He was also the lead vocalist and multi-instrumentalist for the rock band and later solo musical project The Brobecks.
Vices & Virtues is the third studio album by American rock band Panic!
 at the Disco, released on March 22, 2011 on Fueled by Ramen.
 Produced by John Feldmann and Butch Walker, the album was recorded as a duo by vocalist and multi-instrumentalist Brendon Urie and drummer Spencer Smith, following the departure of lead guitarist, backing vocalist and primary lyricist Ryan Ross and bassist/backing vocalist Jon Walker in July 2009.
 The album's artwork was conceptualized by touring bassist Dallon Weekes who was inducted as a full-time member of the band near the end of recording.
Peter Lewis Kingston Wentz III (born June 5, 1979) is an American musician.
 He is best known for being the bassist, lyricist, and backing vocalist for the American rock band Fall Out Boy.
 Before Fall Out Boy's inception in 2001, Wentz was a fixture of the Chicago hardcore scene and was notably the lead vocalist and lyricist for Arma Angelus.
 During Fall Out Boy's hiatus in 2009–12, Wentz formed the experimental, electropop and dubstep group Black Cards.
 He owns a record label, DCD2 Records, which has signed bands including Panic!
 at the Disco and Gym Class Heroes.
 Fall Out Boy returned in February 2013.
Jonathan Jacob "Jon" Walker (born September 17, 1985) is an American musician.
 Formerly the bassist of Panic!
 at the Disco, Walker was also the lead guitarist and occasional split vocalist of The Young Veins (which he founded with former Panic!
 lead guitarist Ryan Ross), now on indefinite hiatus.
 Having went on to release several solo recordings, he is now mostly songwriting and producing.
Jake Sinclair (born March 7, 1985) is an American record producer, audio engineer, mixing engineer, multi-instrumentalist, vocalist, and songwriter.
 His production, engineering, songwriting, and mixing credits include Weezer, Fall Out Boy, Panic!
 at the Disco, 5 Seconds of Summer, Pink, New Politics, Andrew McMahon in the Wilderness, Gin Wigmore, and Train.
 Sinclair co-wrote and produced Panic!
 at the Disco's "Death of a Bachelor" album (which debuted at number one on the US Billboard 200) and produced Weezer's 2016 "Weezer (White Album)".
 Both were nominated for Best Rock Album at the 59th Annual Grammy Awards.
 He co-wrote and produced "Uma Thurman" by Fall Out Boy, which debuted at number one on the U.S. iTunes Chart, reached number 22 on the Billboard Hot 100, and was certified 2X Platinum by the RIAA in December 2015.
 Sinclair received a Grammy nomination for Album of the Year for his work as engineer and bassist on Taylor Swift's "Everything Has Changed" alongside producer Butch Walker.
 He co-wrote and produced the debut single, "She Looks So Perfect" by 5 Seconds of Summer that peaked at number one in over five countries and won "Song of the Year" at the 2014 ARIA Awards.
 Sinclair is the former bassist of the indie/pop rock band The Films and the lead singer and producer of the indie pop duo Alohaha.
George Ryan Ross III (born August 30, 1986) is an American musician, singer, and songwriter best known for his work as the lead guitarist and primary songwriter of the band Panic!
 at the Disco before his departure in 2009.
 Ross and former Panic bassist Jon Walker are the founding members of the band The Young Veins, in which Ross is the lead vocalist.

Question: Who was a bassist for Panic! at the Disco and lead vocalist for the Brobecks?
Answer: Dallon Weekes