There's a rumour going around that former 'Doctor Who' star Matt Smith is set to return as the Doctor following the departure of Peter Capaldi, despite the fact that no Doctor has ever returned on a long-term basis before. Moffat, who is also preparing to leave the show in 2017, talked about the actor's regret about leaving. 

Matt SmithMatt Smith wants to come back to 'Doctor Who'

Series 10 is set to air next year and will be the final series starring Peter Capaldi. There's no word yet on who might replace him, but Moffat has hinted that Smith could be a contender once again. While it's very unlikely that Smith will come back to the show (except on a brief cameo basis) given that no other Doctor ever has, whispers of his return started after 'Doctor Who' writer Steven Moffat confessed that the actor missed the show. 

Matt Smith, also known as the Eleventh Doctor, left the show in 2013 after three series. '[He is] quite open about how much he misses it, and how much he wishes he hadn't left', Moffat told The Mirror. He'd also previously confessed that he never wanted him to leave in the first place. 'Matt, who was a friend and ally, was leaving. I couldn't get him to stay. It felt like everything was blowing up around me', he said.

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While Smith is reportedly desperate to return to 'Doctor Who', it's not as if he's short on work at the moment. Since he departed the show, he has been in 'Terminator Genisys' and 'Pride and Prejudice and Zombies'. He also has three other screen projects coming up: the action thriller 'Patient Zero', Robert Mapplethorpe biopic 'Mapplethorpe' and Netflix history drama 'The Crown'. Currently, he's appearing in Anthony Neilson's play 'Unreachable', his first stage appearance since 2013's 'American Psycho'.

The last time we saw an old Doctor make a comeback was the 2013 special episode 'The Day of the Doctor', which featured cameos from tenth Doctor David Tennant and fourth Doctor Tom Baker.