Who is Bill Potts’ birth mum? That’s the Doctor Who question we’ve all been asking since we first caught a glimpse of her in series 10 opener The Pilot.
We’ve had fleeting glimpses of the elder Potts (if that IS her surname) throughout the current run, but did you know we’ve actually seen her in Doctor Who before?
It turns out she’s actually a Time Lord. Well, sort of...
Who plays Bill's mum in Doctor Who and when have we seen her before?
Actress Rosie Jane, who portrays Bill’s mum, also played a Time Lord of the High Council in 50th Anniversary special The Day of The Doctor.
You might have spotted her ducking for cover as Gallifrey shook, while all 13 incarnations of The Doctor banded together to save their home planet.
And if you think about it, this means she's technically encountered Peter Capaldi's 12th Doctor before – even if their exchange was wordless and eye to eye, instead of face-to-face.
Who is Rosie Jane?
Rosie Jane is a British actress who studied drama and English at the University of Bristol before moving to the East 15 acting school in Essex.