When D:Ream broke through into the charts, the band's main touring line-up consisted of core member Peter Cunnah (vocalist, songwriter), Al Mackenzie (musician), and Cian McCarthy. Other main performers included physicist Brian Cox who played keyboards for several years while studying for his physics PhD degree, Derek Chai on bass, and drummer Mark Roberts. The group also used a number of guest vocalists – such as T.J. Davis, who is featured as co-lead vocalist on "The Power (Of All the Love in the World)", one of the singles taken from their second album, as well as providing backing vocals on many other songs.