Before she takes over the lead role in Doctor Who, Jodie Whittaker will be appearing on our screens as a very different doctor... and a fake one at that.
In BBC One thriller Trust Me, Whittaker plays Cath Hardacre, a nurse who loses her job after she turns whistle-blower.
Wanting to provide a better life for her young daughter, she steals her best friend's identity as a senior doctor and lands a job in an Edinburgh hospital (a colleague amusingly describes the A&E department as "like Braveheart with bad-tempered pensioners".)
Armed with her nursing knowledge and some medical textbooks, Cath sets out to bluff her way as an experienced emergency medic.
Of course, it doesn't all go smoothly. Trust Me contains several squirm-inducing scenes of medical procedures that don't go by the book
An early encounter sees her straighten a man's broken foot having forgotten to give him an anaesthetic. Imagine the screams.
Then there's a heart-stopping - and heart-breaking - sequence involving the victims of a car crash.
"There was blood squirting everywhere," says Whittaker, at a press screening that was held before the recent announcement she was to replace Peter Capaldi in Doctor Who.
Like her character in Trust Me, the blood is of course fake, but that doesn't make it any less excruciating to watch.
"The prosthetics were amazing," Whittaker adds. "And there were phenomenal actors coming in and committing to the sound of pain."
'It's not that hard to fake it'
Trust Me was written by Dan Sefton, a real-life A&E doctor, whose other TV writing includes Good Karma Hospital and Mr Selfridge.
"I think there are loads of people who aren't real doctors," says Sefton, somewhat chillingly.
"It's not that hard to fake it if you have some qualifications. Part of this thing is that people don't ask too many questions. We set this deliberately in a place that was on the periphery and struggling to recruit."
Sefton also reveals that there had once been a case of a bogus doctor working in his own hospital.
"He only got found out through some administrative thing, because he was actually pretty competent," he recalls.
"Often these doctors are very professional and get along very well with their colleagues. The only flaw is that they aren't real doctors."
As well as writing the tense hospital scenes, Sefton also helped give the actors some medical training.
That included teaching Whittaker how to insert a needle into his own arm.
"I got it in your vein first time," the Broadchurch actress notes proudly. "But I forgot to put the cap on and you started bleeding, which was a bit of a panic!"
Whittaker says she was fine with the "physical and emotional stuff" that the script demanded. "The thing I struggled most with - and that comes from failing over half my GCSEs - was the pronunciation of medicines."
The rest of the cast includes Emun Elliott as an A&E doctor, Sharon Small as the consultant in charge, and Inbetweeners star Blake Harrison as Cath's ex-boyfriend and father of their daughter.
Whittaker describes herself as big fan of the NHS. "You don't have to be rich to be poorly," she says. "There are obviously problems - we all read the news - but I feel that the thing you want to celebrate is the day-to-day people: The doctors and nurses."
Sefton admits that what fascinates him is WHY people pretend to be doctors.
"Men almost always do it for egotistical reasons," he says. "They are often fantasists. They want to be somebody who is impressive.
"Women tend to do it more much more practical, interesting reasons. That's one of the reasons I chose a female protagonist for this drama.
"I was much more interested in looking at how the act of lying changes someone who is an essentially honest person."
Trust Me begins on Tuesday 8 August on BBC One.