Michael Bentine
From Tardis Wiki, the free Doctor Who reference
Michael Bentine played an interviewer in the It's a Square World sketch The Doctor's New Invention, which featured Doctor Fotheringown (a parody of the First Doctor) as played by Clive Dunn. He was later considered for the role of the Fourth Doctor after Jon Pertwee left in 1974.
The sketch was released on DVD alongside The Aztecs: Special Edition.