Rory Bremner appeared on the British edition of Whose Line.
Already famous as an impressionist, Rory made one inconsequential appearance, before returning several seasons later for an extended run. He was somewhat under-used, although he was always in demand for impressions - including in the Credits Reading.
Rory is famous for a number of his impressions. Among these are his Murray Walker opposite Greg Proops in Sports Commentators and a number of Party Quirks appearances as - variously - Clive Anderson, English football commentator John Motson and even as Tony Slattery.
The "Rory as Tony" quirk is particularly well known in Whose Line circles, especially Tony's reaction. After he realized what the quirk was, Tony appeared particularly unimpressed before commenting "Oh ha ha ha" and refusing to name the quirk.
Rory's appearances (UK)
Series 1: Episode 1
Series 6: Episodes 6 and 10
Series 8: Episodes 2, 11 and 14
Series 9: Episodes 1, 11 and 17