When they upended the Doctor Who universe with the casting of the first female "incarnation" of the iconic TV time traveller, it was a given the rulebook had been tossed out the window.
Now, the role of The Doctor's dutiful female companion - the one who historically screamed a lot, particularly when the Daleks were approaching - is to be filled by a 57-year-old man.
Comedian-turned-actor Bradley Walsh is to become the companion to Jodie Whittaker's female Doctor Who ... and his character's name is Graham.
The 57-year-old actor's credits include Coronation Street and Law & Order: UK; he has also hosted game shows such as The Chase and Cash Trapped.
Graham is one of three companions joining the series: the other two are former Hollyoaks stars Mandip Gill and Tosin Cole, who play Yasmin and Ryan.
The announcement of Whittaker's casting as The Doctor earlier this year triggered a media furore, though to be fair it was met with almost overwhelming positivity by Doctor Who fans.
The "furore", though, became a self-fulfilling prophecy: the media focused largely on a handful of disgruntled comments on social media to frame the announcement as controversial, when in truth it was barely that.
Whittaker is replacing actor Peter Capaldi, who has been in the role since 2013.
Walsh would replace Bill Potts, played by Pearl Mackie, who served as "companion" to Capaldi's Doctor.
The change of actor within the Doctor Who narrative was a plot conceit established in the 1960s when the actor who originated the character, William Hartnell, became ill and was unable to continue working on the series.
But the notion of the Doctor's "companion" has existed for the entire life of the series.
Initially, Hartnell's Doctor was accompanied on his travels by his granddaughter Susan (Carole Ann Ford) and two of her schoolteachers Ian Chesterton (William Russell) and Barbara Wright (Jacqueline Hill), who forced their way into the Tardis after following Susan home.
But later Doctors were accompanied by a variety of companions, including journalist Sarah Jane Smith (Elisabeth Sladen), the warrior Leela (Louise Jameson), would-be "spy" Jo Grant (Katy Manning) and soldier Brigadier Lethbridge-Stewart (Nicholas Courtney).
And while the notion of a female Doctor was surprising at least, the Doctor's Tardis has been filled with companions of all genders, as well as a couple of robots: K-9 the dog and Kamelion.
Walsh said he remembered watching Hartnell's Doctor as a child.
"Black and white made it very scary for a youngster," he said. "I was petrified but even though I'd watch most of it from behind the sofa through my fingers, I became a fan."
Walsh said he then queued as a boy to watch Peter Cushing's Doctor in the standalone colour Doctor Who features produced in the 1960s. (Those films have no narrative connection to the TV series.)
he change of Doctor and companion comes as executive producer and showrunner Steven Moffat is bowing out, to be replaced by Chris Chibnall.
Capaldi announced his plan to step down in January, 2017; the upcoming Christmas episode, The Doctors, will be his last.
He made his debut in the series, briefly, in the program's 50th anniversary special, The Day of the Doctor, which was broadcast in 2013; he later made his formal debut in the Christmas special, The Time of the Doctor.
Except for two breaks, between 1989 and 1996 and 1996 and 2005, Doctor Who has been in production since 1963.
