10 Doctor Who Guest Stars Who Came Back In Bigger Roles

3. Freema Agyeman

Winning the role of the Doctor's coveted companion is one of the most prestigious performance accolades on the British televisual market but for Freema Agyeman her debut as Martha Jones in Series 3 wasn't the first time she'd brushed shoulders with the Tenth Doctor. In fact, she had previously appeared - in a completely different role altogether - just two episodes before her introduction as the show's new leading lady. In the first part of the Series 2 finale, Agyeman appeared as Adeola Oshodi (or just 'Adi' for short), an ill-fated Torchwood technician who ended up being infiltrated by the Cybermen and used as a pawn to partake in their evil bidding. She only snuck away from her desk for a cheeky snog with her colleague but it really wasn't worth it in the end when she ended up being seized by the metal monsters and having her brain turned to mush by an internal upgrade. What a way to go. Fans of Freema didn't have long to wait to see her again, though. She was given a new on screen persona (she's Martha Jones, who the hell are you?) and promptly stepped aboard the TARDIS for adventures anew as a fully fledged TARDIS resident in Spring 2007. The reappearance of a guest actor is usually ignored but in this case - owing to the fact that her two characters were so close together - the writers obviously decided that it warranted some kind of narrative explanation. As such, Adeola's uncanny resemblance to the Doctor's new companion was written off in passing when Martha mentioned that she'd had a cousin who died during the Battle of Canary Wharf, and thus the matter was swiftly swept under the carpet and never mentioned again. At least it's something, right? Speaking of guest stars who were transformed into companions...