10 Doctor Who Guest Actors Who Also Played The Doctor

10. David Warner

David Warner was reportedly Steven Spielberg's suggestion for Doctor Who in the TV movie, but it's said that the actor didn't want to be tied down to a long-running series. Warner finally made an appearance in the series proper in Cold War, a minor and some might say disappointing role in an episode written by his friend Mark Gatiss.

The two had previously played the Doctor and Master respectively in a Big Finish audio entitled Sympathy for the Devil. It was released as part of their Unbound series, during Doctor Who's 40th anniversary year. Each play was a "What If?" Doctor Who story, such as "What if the Valeyard had won?" or, in Warner's case "What if the Doctor was never UNIT's scientific advisor?"

Jonathan Clements' story finds this alternate Third Doctor accidentally sent to Hong Kong 1997, rather than England 1970. He finds his old friend the Brigadier running a bar in the city, after being dishonourably discharged from UNIT. The two old men join forces against the Master and some ancient alien parasites. It's a great Doctor Who story, and Warner was so good in the role that he's continued to play the so-called Unbound Doctor in numerous audios for Big Finish.