In a shock revelation, Doctor Who series 12’s fifth episode revealed that unassuming tour guide Ruth Clayton (Jo Martin) was actually another version of the Doctor in disguise, with Jodie Whittaker’s incarnation of the Time Lord shocked to discover she had a past regeneration she couldn’t remember.
And since the reveal that Martin was the Doctor fans have had all sorts of theories about where she could fit into the complicated Doctor Who timeline, with the most popular idea being that this is a version of the Doctor from a parallel universe.
But now, series boss Chris Chibnall has rubbished this particular theory, saying that Martin’s new Time Lord is “definitively the Doctor.”
“The important thing to say is – she is definitively the Doctor,” he told the Mirror. “There's not a sort of parallel universe going on, there's no tricks.
"Jo Martin is the Doctor, that's why we gave her the credit at the end which all new Doctors have the first time you see them. John Hurt got that credit.”
In other words, she has to exist somewhere in the past of Jodie Whittaker’s Doctor – and whether she turns out to be the real First Doctor, a forgotten in-between version like John Hurt’s War Doctor or something else, Chibnall says we will get some answers as the series continues.
“There will be answers to some of these mysteries this series,” Chibnall said. "But as ever with Doctor Who, answers often reveal new questions. It's all very deliberate.”
Noting that some fans were already incensed by the idea of changes to Doctor Who history, he added: “We’re telling an ongoing story and there are plenty of things in Doctor Who that change all the time.
“But I’m very aware of the history and very aware of the continuity. It’s a delightful thing.
"But stories are ongoing pieces of fiction. They develop and evolve. My job is to be bold with the storytelling and have fun.”
In other words, we all need to relax a little bit and let this new story play out. If nothing else, it gives us plenty more fun theorising to get on with for the next few weeks…
Doctor Who continues on Sundays on BBC One