It was said in a light hearted way on The Big Fat Quiz Of The Year.
James Acaster is a very funny comedian, I couldn't see him doing either role unless it was a spoof for comic relief.
They will cast a man in both roles, I can't see them casting another female Dr Who for a bit. There will be another, but the next two will be male.
I'm just wondering how it will be announced, but there'll be some sort of accompanying fanfare regardless.