The best theory for how David Tennant could succeed Jodie Whittaker as the Doctor is reminiscent of a classic Doctor Who story from Tom Baker's time on the show. Jodie Whittaker is due to bow out as the Doctor in a special feature-length episode in the Fall, with Sex Education's Ncuti Gatwa cast as the new Doctor. However, the return of David Tennant and Catherine Tate to the series for the 60th anniversary suggests Whittaker's regeneration into Gatwa will be more complex than first thought.
David Tennant has been spotted filming in London for the 60th, wearing a previously unseen variation of his classic Tenth Doctor outfit. This has led to speculation that David Tennant is replacing Jodie Whittaker as the Doctor, rather than reprising his original incarnation. The Tenth Doctor's vanity was ridiculed by the Eleventh Doctor in «The Time of the Doctor» when he revealed that he once squandered a regeneration by keeping the same face in Doctor Who season 4, episode 13 «Journey's End». However, the precedent for a Doctor regenerating, or degenerating into old faces was set back in the 1970s.
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Debuting in 1979, just over halfway through Tom Baker's tenure as the Doctor, Doctor Who Weekly was a magazine aimed at kids that featured posters, articles, and comic strips. It also introduced numerous plot ideas that Doctor Who would reuse in its 21st-century incarnation. Under editor Dez Skinn, Doctor Who Weekly told stories of Kroton, the Cyberman with a soul, and of pirates fighting Sea Devils. In the two-part comic strip story «Timeslip», printed in issues 17 and 18 of Doctor Who Weekly, it also introduced the concept of retro-regeneration decades
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