The 58-year-old announced yesterday that he was stepping down after playing the Time Lord since 2013.
He made the unexpected announcement when he was discussing the upcoming 10th series on Jo Whiley’s BBC Radio 2 show.
When asked what was in store for fans, he told the DJ: ”I suppose the big thing for me is that it will be my last. It will be the end for me."
Immediately after the news, viewers took to Twitter to express their thoughts over the Scottish actor’s exit.
One person wrote: “Peter Capaldi is leaving Doctor Who. But he was my favourite doctor!”
Peter Capaldi is stepping down from playing the Time Lord in Doctor Who
Peter Capaldi has been in the sci-fi drama since 2013
I suppose the big thing for me is that it will be my last
“Aaaaand Peter Capaldi has broken my heart. Such an amazing Doctor,” said another.
A third fan was also upset with the news: “I had a sinking feeling it was coming, but I am still gutted to hear Peter Capaldi is leaving #DoctorWho. He's absolutely phenomenal.”
But some viewers were quick to mention who they want as the new Doctor in the long-running sic-fi drama with Tom Hiddleston, Rupert Grint and Colin Morgan thrown into the mix.
One fan said: "Hearing the news about Peter Capaldi, can't help thinking Tom Hiddleston would make a great #DoctorWho."
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"Peter Capaldi is a genius and a great Doctor, I'm so sad he's leaving. However, I'm now campaigning to make #ColinMorgan the next Doctor," enthused another.
One social media user wants the return of a former actor: "Just when I started giving Peter Capaldi a chance, he's leaving Doctor Who? Well, is there a way to get David Tennant back?"
"@DoctorWho_BBCA please can the doctor be a ginger next? Rupert Grint perhaps?," asked one viewer.
Doctor Who through the years
Mon, August 22, 2016
Peter Capaldi is the Twelfth Doctor to appear in the iconic British TV series. Take a look at the time-travelling Doctors through the years.
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The ability of the Time Lord to regenerate into a different sex has left some fans wondering if it is time for a woman to take the role.
"So with Peter Capaldi leaving, seems like the next Doctor will probably be a woman, right? I know people were pushing for that last time…" A Twitter user asked.
Another said: "Sad to see Capaldi go. If we're moving towards a female Doctor Hayley Atwell would be perfect for the role #DoctorWho."
"If Peter Capaldi is leaving Dr Who, can we have @sueperkins as the next Doctor please?" Begged a third.
For now, Peter will still be appearing in the new series and will continue playing the Doctor until after this year's Christmas Special.
Doctor Who will return to BBC One on Saturday 15 April