Doctor Who: 10 Best NuWho Guest Stars Ever

Guest stars are a huge part of the revived series of Doctor Who. While the main focus of fans and indeed most episodes tends to be on the Doctor and his various companions, someone has to play the people they meet on their adventures to strange and wonderful new worlds.

The world's longest running sci-fi programme offers a variety of roles for guest cast to play. Accept a part and you could end up as an alien overlord,  a historical figure or even a computer programme. Imagine turning up to work to spend a day as an interdimensional pirate or a secret agent involved in extraterrestrial affairs and you can see why so many people love taking time out of their schedule to be on Doctor Who!

They're not just filling in the gaps, of course. Guest stars can attract fans of other show to the show - for example, the fandom combination SuperWhoLock might not nearly be as popular on social media sites like Tumblr if it hadn't been for Mark Sheppard popping up in Series 6. That's not all, though. A guest actor putting in a star turn with their performance can elevate an episode from the realms of being good to absolutely great.

With the hype train rolling on guest stars for Series 9 (Maisie Williams! David Schofield! Other people!), it's time to look back at some of the best guest stars of the revived series so far. Click "Next" to begin. 

Despite being a solid character actor, Colin Salmon may not be the first name that comes to mind when thinking either of a famous British actor or a Doctor Who guest star. However, his role in Silence in the Library/Forest of the Dead is extremely underrated.

He played Doctor Moon, a psychiatrist for a young girl called Cal, who turned out to be essentially the anti-virus programme on the library's futuristic central mainframe where the young girl lived. He never actually met the Doctor himself, but that didn't mean he didn't leave an impression.

While he was arguably overshadowed by the first appearance of River Song, Salmon's calm and controlled performance sets off the sense that not everything is quite right. Especially when it comes to his delivery of, "Then... you forgot", he oozes a sense of being sinister while also trying to help. Additionally, there's an element of unspoken authority even behind the minor deference to his 'clients'.

All these various aspects contribute to what is a fantastic performance and Dr Moon is central to how the episode works, creating the  ominous sense to the overall mystery behind the plot.