From Longman Dictionary of Contemporary Englishdouble actˈdouble act noun [countable] APtwo actors, especially comedians, who perform together
Examples from the Corpus
double act• The act now took the form of a double act.• Bill used to be half of a double act with Dave Allen.• They make a good double act in the Treasury team, where she is shadow Chief Secretary.• It could have been an interesting double act but it was bunkered immediately by all the showbiz flannel.• The reason for this double act becomes obvious the minute you set off. 