10 Doctor Who Guest Actors Who Also Played The Doctor
7. Derek Jacobi
Derek Jacobi's Master was one of the great surprises of the Russell T Davies era. He'd played the character before of course, in the ill-fated Scream of the Shalka series, but here he was albeit briefly as a decidedly menacing Master. Of course, a brief cameo is no barrier to future roles in Doctor Who, and Jacobi has been playing the character for Big Finish since 2017.
Derek Jacobi had previously worked with Big Finish, most notably in 2003 as part of their Unbound series. Deadline, the play that stars Derek Jacobi as Martin Bannister isn't technically a Doctor Who story, rather it's about the absence of Doctor Who. Set in an alternate reality where Doctor Who never made it past the pilot, Jacobi's character is the aging and confused screenwriter who wrote the first episode.
As the play goes on, Bannister begins to believe that he is the Doctor, and so listeners get to hear Derek Jacobi act out alternate versions of scenes from An Unearthly Child and The Daleks. Written by Dalek writer Robert Shearman, it's a dark and melancholic tale of wasted opportunities and dashed dreams. It also suggests that life is just that bit brighter with Doctor Who in it.