Tessa Peake-Jones

 played Marta in The Time of the Doctor.

Although she has had a varied acting career, by far her most well-known role is that of actress (and occasional stripper) Raquel Turner in the classic sitcom Only Fools and Horses. By coincidence, in Raquel's debut episode (1988's Christmas special Dates, broadcast exactly 25 years before The Time of the Doctor) she had mentioned that her biggest acting role to that date had been a bit part in a Doctor Who episode "about ten years ago". She also had a recurring role in The Demon Headmaster, the title role of which was played by Terrence Hardiman.