WARNING: The following article contains spoilers for "Fugitive of the Judoon," the fifth episode of Doctor Who Series 12.

The long-running British sci-fi television series Doctor Who just made history by introducing the very first Black version of the time-travelling hero known as the Doctor.

The fifth episode of Doctor Who Series 12 -- "Fugitive of the Judoon" -- introduces the character Ruth Clayton, played by Jo Martin. Over the course of the episode, it is revealed the Ruth persona is merely a fabrication, and Martin's character is actually a previously unseen regeneration of the Doctor (akin to John Hurt's War Doctor from the Series 7 finale "The Name of the Doctor" and the Doctor Who 50th anniversary special "The Day of the Doctor.")

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Doctor Who star Jodie Whittaker herself made history when she stepped into the shoes of the Doctor to play the first female incarnation of the character. However, Jo Martin's secret version is not only the very first Black version of the doctor, but technically also retroactively makes Whittaker's version only the second female Doctor in the franchise's known canon.

Doctor Who stars Jodie Whittaker as the 13th iteration of the titular Time Lord. Whittaker is joined by co-stars Bradley Walsh, Tosin Cole and Mandip Gill in a series spearheaded by showrunner Chris Chibnall. The next episode is set to air on the BBC on Feb. 2. The new season and all previous 11 seasons will stream on HBO Max later this year.

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(via Radio Times)