Long-term ‘Doctor Who’ fans had a serious blast from the past during Saturday’s (1 July) series finale, when the First Doctor made a shock appearance.
The closing moments of the episode saw the first incarnation of the Timelord return - albeit played by a different actor, David Bradley.
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The 12th and first Doctor will star in the Christmas special
ITV
The cliff-hanger ending saw Peter Capaldi’s Doctor fatally shot by a Mondasian Cyberman and begin to regenerate.
Stepping out of the TARDIS into an arctic landscape, he fought off the glowing regeneration energy and fell to his knees, vowing that this time he would not live on and change into a new Doctor.
This was declared “ridiculous” by an approaching figure, who stepped forward through the snow to reveal himself as the very first Doctor.
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ITV
The story featuring the two Doctors will continue during this year’s Christmas special, where Peter will make his final appearance as Doctor, and the new one is introduced to fans.
William Hartnell played the original Doctor between 1963 and 1966, died in 1975, aged 67.
David Bradley previously played the role of William - and consequently the First Doctor - in BBC Two’s 2013 biopic about the beginning of the sci-fi series, ‘An Adventure in Space and Time’, which was written by Mark Gatiss.
Kris Marshall remains the favourite to become the 13th Doctor, with an official announcement expected on their identity in the next few months.
Who Will Replace Peter Capaldi In 'Doctor Who'? All The Rumours So Far...
Kris Marshall(01 of10)
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Honestly speaking, the former 'My Family' actor is probably the horse we'd be putting our money on.
Not only is he the bookies' favourite for the job, various sources have claimed that producers want him to follow on from Peter Capaldi, and he mysteriously stepped down from 'Death In Paradise' around the time the Time Lord vacancy opened up. (credit:Venturelli via Getty Images)
Ben Whishaw(02 of10)
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But, of course, the most obvious solution isn't always the right one.
'James Bond' actor Ben Whishaw (who plays Q in the spy saga) was among the names initially linked with the job, although it's been a long time since we've seen his name linked with taking on the role.
Whether this is because he's ultimately not been chosen or because the BBC is trying to keep things secret remains to be seen. (credit:David M. Benett via Getty Images)
Richard Madden(03 of10)
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An insider told The Sun earlier this year: "[Richard] will be high on the list of potential replacements when the formal casting process gets under way.
“He’s very different to Peter, obviously a lot younger, but part of the appeal to regenerating the Doctor every few years is to reinvent the character." (credit:Barcroft Media via Getty Images)
Frances De La Tour(04 of10)
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When departing Time Lord Peter Capaldi was asked for his choice for the role, he not only said he wanted a woman to get the gig, but also gave Frances as his top pick.
With predecessors like Matt Smith, David Tennant and Christoper Ecclestone, we'd be intrigued to see what the 'Vicious' actress brought to the iconic role of the Doctor. (credit:Julian Parker via Getty Images)
David Harewood(05 of10)
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Another name bookies have repeatedly thrown out, David has said he thinks it's time that a BAME or female actor take over the lead role in 'Doctor Who'.
Admitting it was "nice to be in the running", he told the BBC: "It needs to do something different, so I think it's either going to be a black person or a woman. It would just bring a different flavour to it." (credit:David Crotty via Getty Images)
Phoebe Waller-Bridge(06 of10)
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As the discussion about whether it's time for a woman to take charge of 'Doctor Who' continues, Phoebe's is a name that has cropped up repeatedly.
The 'Fleabag' creator spoke about the rumours in May, saying it would be a "great time" for a woman to land the job, adding: "There are so many great actresses out there who I think would kill it." (credit:Rabbani and Solimene Photography via Getty Images)
Olivia Colman(07 of10)
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Similarly, Phoebe's 'Fleabag' co-star Olivia Colman has also been linked with potentially succeeding Peter Capaldi.
One of Britain's leading TV stars, former Doctor (and her 'Broadchurch' co-star) David Tennant added that she'd be "a magnificent choice" for the part. (credit:Dave J Hogan via Getty Images)
David Bradley(08 of10)
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David previously starred as William Hartnell - the actor behind the First Doctor - in the 2013 biopic, 'An Adventure In Space And Time'.
When quizzed about rumours he'd be taking over the role of the First Doctor again, he teased (via the Birmingham Mail): "Who knows? You didn't hear it from me, that's all I can say." (credit:Albert L. Ortega via Getty Images)
Damien Molony(09 of10)
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Damien was named by 'Doctor Who' writer Toby Whithouse as a "terrific" choice to take over the role, and he'd certainly work amid claims producers are hoping to recruit a younger, David Tennant-esque star. (credit:John Lamparski via Getty Images)
Chiwetel Ejiofor(10 of10)
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In the same interview in which Damien's name was mentioned, Bafta-winner Chiwetel was also suggested as an "ideal choice" for the part.
Series writer Toby Whithouse told Digital Spy that he'd be "terrific" as the Thirteenth Doctor. (credit:Albert L. Ortega via Getty Images)