UFO were an English rock band formed in London in 1968. They became a transitional group between early hard rock and heavy metal and the new wave of British heavy metal. The band's final lineup consisted of vocalist Phil Mogg, lead guitarist Vinnie Moore, rhythm guitarist and keyboardist Neil Carter, bass guitarist Rob De Luca, and drummer Andy Parker. They had gone through several line-up changes, leaving Mogg as the only constant member, and had disbanded three times. The band also featured former Scorpions guitarist and Michael Schenker Group (MSG) founder Michael Schenker, who was a member of UFO from 1973 to 1978 and rejoined the band sporadically between 1993 and 2003, when Moore replaced him. In May 2018, Mogg announced that he would retire from UFO after one last tour as a member of the band in 2019; however, their farewell tour was set to conclude in 2022 before it was cancelled, due to Mogg's health issues. Mogg confirmed UFO's third disbandment in April 2024.

Scorpions are a German hard rock band formed in Hanover in 1965 by guitarist Rudolf Schenker. The lineup from 1978 to 1992 was the most successful incarnation of the group, and included Klaus Meine (vocals), Rudolf Schenker, Matthias Jabs, Francis Buchholz (bass), and Herman Rarebell (drums). The band's only continuous member has been Schenker, although Meine has appeared on all of Scorpions' studio albums, while Jabs has been a consistent member since 1978, and bassist Paweł Mąciwoda and drummer Mikkey Dee have been in the band since 2003 and 2016 respectively.