Nowadays, seeing actors from Doctor Who showing up in other films and TV shows is not a big deal. I mean, it might be fun and cool, but it’s not a surprise.
(Daily Doctor Who #6)
But it wasn’t always that way. When it comes to the classic series, it was quite a rare and unusual thing to find most of the Doctor Who regulars in anything else. Maybe this was partially due to my being an American with a relative lack of British TV.
So whenever I recognized someone or saw their names in the credits, it was quite a treat.
Here’s some things I can remember–not a comprehensive list from the internet, but just one movie or program that I can remember seeing each of these people in (for some, I am choosing from amongst a bunch of stuf, but limiting myself to one for the sake of brevity). If you are looking to see your favorite Doctor Who star in something unrelated to Doctor Who, here are some possibilities…
William Hartnell (The First Doctor) – Sergeant Will Buckley in The Mouse That Roared–a soldier from the tiny nation of Grand Fenwick who helps his country accidentally conquer the United States in this 1959 comedy starring Peter Sellers.
William Russell (Ian Chesterton) – Soren, the escape artist in charge of security for an ambitious escape plan in The Great Escape (1963).
Carole Ann Ford (Susan Foreman) – A blind girl named Bettina who is menaced by killer plants in Day of the Triffids (1962). She screams here as she’s threatened by monsters, so it’s a bit reminiscent of her appearance in Doctor Who, except she dies.
Jean Marsh (Sara Kingdom, and other roles) – Rose, the parlourmaid in the highly successful and well-regarded TV series Upstairs, Downstairs, which Jean Marsh co-created.
Patrick Troughton (The Second Doctor) – Mr. Jessop in the British TV drama Nanny starring Wendy Craig. This was a long time ago on a fuzzy TV, and I don’t remember it well, but I had the impression it was good. I’d be curious to revisit it again.
Jon Pertwee (The Third Doctor) – Brigadier Whitehead, a slightly crazy military man who met an untimely ends in the episode of The Avengers, From Venus with Love.
Caroline John (Liz Shaw) – I don’t remember for sure when I became aware of this–I was just reminded of it when looking her up for this post–but Caroline John appears in Love, Actually as Liam Neeson’s stepson’s grandmother.
Roger Delgado (the Master) – I have a vague memory of seeing him get beat up by John Steed in an episode of The Avengers, though not one of the ones I’ve been watching recently. Research tells me it was probably Stay Tuned, from Season Seven.
Richard Franklin (Captain Mike Yates) – He was a hapless former Federation soldier in an episode of Blake’s 7 entitled Aftermath, who was ready to strike out into a new life, when he was suddenly attacked and murdered by some angry natives.
Tom Baker (the Fourth Doctor) – He was the evil magician Prince Kouri in the film The Golden Voyage of Sinbad that I only recently watched.
Ian Marter (Harry Sullivan) – He had a small part in an episode of Sherlock Holmes with Jeremy Brett. He was a police officer in the episode The Musgrave Ritual.
Louise Jameson (Leela) – She played Louise’s mother in a couple of episodes of the oft-brilliant show Doc Martin.
Lalla Ward (Romana, 2nd incarnation) appeared as Ophelia in a British TV version of Hamlet in 1980.
Anthony Ainley (the Master from the 1980’s) – Dietz, a German U-boat officer from The Land That Time Forgot, which I’ve only seen when it was featured on Mystery Science Theatre 3000
Peter Davison (the Fifth Doctor) – Quite a few things, but the most obvious is as Tristan in the TV series, All Creatures Great and Small.
Mark Strickson (Turlough) – He once played young Scrooge in the 1984 version of A Christmas Carol starring George C. Scott.
Colin Baker (the Sixth Doctor) – He played a maniac called Bayban the Butcher in an episode of Blake’s 7 called City on the Edge of the World.
Nicola Bryant (Peri Brown) once appeared on the Blackadder’s Christmas Carol as a screeching woman named Millicent.
Bonnie Langford (Mel) was in an episode of Marple, called By the Pricking of My Thumbs.
Sylvester McCoy (the 7th Doctor) – Showed up dancing like a lunatic in the TV film made out of various charity skits known as The Secret Policeman’s Ball, which I happened to see at a friend’s house.
Sophie Aldred (Ace) – She showed up like 2 episodes of Eastenders, one of which I just happened to tune into right around the time she was on screen, helping to facilitate one of the regular cast members leaving the show, I think.
And that’s that! Who am I missing? It seems I have never seen any other non-Doctor Who performances by Jacqueline Hill, Maureen O’Brien, Peter Purves, Adrienne Hill, Jackie Lane, Anneke Wills, Michael Craze, Frazer Hines, Deborah Watline, Wendy Padbury, Nicholas Courtney, John Levene, Katy Manning, Elisabetn Sladen, John Leeson, David Brierley, Matthew Waterouse, Sarah Sutton, Janet Fielding, and Gerald Flood. Quite a few, really.
Any suggestions?
Blue Towel Productions 
John Levene I also remember as a police constable in Psychomania. John Leeson also appeared in Blake’s 7: Mission To Destiny. And Nicholas Courtney had guest starred in The Avengers.