5 Seconds of Summer (also known as 5SOS) are a 4-piece Australian pop rock/pop punk band. Formed in Sydney, New South Wales, Australia in 2011, the band consists of Luke Hemmings (lead vocals, guitar), Michael Clifford (guitar, vocals), Calum Hood (bass guitar, vocals) and Ashton Irwin (drums, vocals). The group were originally YouTube celebrities, posting videos of themselves covering songs from various artists in 2011. From there, they gained a small following in 2012 after posting a series of cover versions of popular songs onto YouTube