Derek Jacobi

Derek Jacobi (sometimes credited as Sir Derek Jacobi) is a British actor, knighted in 1994 for his services to theatre.

Out of the three roles he has acted for Doctor Who he has played The Master twice, and a role usually occupied by the Doctor.

Big Finish - Doctor Who Audio Dramas

 * Deadline

Doctor Who TV Stories

 * Utopia

Doctor Who Webcasts

 * Scream of the Shalka

Utopia
In the Tenth Doctor episode Utopia Derek played the part of Professor Yana who later found out he was really The Master.