And, of course, the 14th Doctor was played by David Tennant who ended up reuniting with Donna Noble (Catherine Tate) where he continues to live now after Ncuti’s version bi-generated out of him (which could come to play in a later theory…)

Piper, now 42, originally played companion Rose Tyler in 2005 alongside Christopher Eccleston’s Ninth Doctor. She went on to appear opposite David Tennant and was later revealed to be the mythical "Bad Wolf" - a mysterious, universe-shaping figure. Now, she’s taken the role full circle by stepping into the shoes of the Doctor herself.