John Hurt's appearance as an a unidentified incarnation of The Doctor during the series seven finale of 'Doctor Who' had fans scratching their heads as to how he will fit in the the Time Lord's timeline.
However, a costume designer for the sci-fi series has apparently confirmed that the actor will play a 'dark Doctor' who provides a missing link between the incarnations played by Paul McGann in the 1996 TV movie and Christopher Eccleston when the series was revived in 2005.
According to The Mirror, Howard Burden is reported to have made the admission during Prince Charles and Camilla's visit to the 'Doctor Who' set on Wednesday.
He apparently said: "There was a gap between Paul McGann playing the Doctor and Christopher Eccleston, when we didn’t see a regeneration, and John Hurt will fit into that gap. He is a past Doctor, not a future Doctor."
Other theories suggested by fans included that he was a 'Valeyard' (an amalgamation of the darker side of the Doctor's nature) or a pre-William Hartnell (who played the first Doctor) incarnation.
Hurt is set to appear in the show's special 50th anniversary episode alongside current Time Lord Matt Smith and assistant Jenna-Louise Coleman, along with former stars David Tennant and Billie Piper.
The episode is set to air in November.
Earlier today it revealed that Russell T. Davis contemplated bringing back former Doctor Tom Baker when the series was revived in 2005.
Fansite Blogtor Who reported Russell as saying: "I remember, actually, someone in the room said, 'Why don't we bring Tom Baker (the fourth doctor) back?' and we all said, 'Yes!' I was sitting there, going with anything, 'Yeah, that'd be great!'."