Doctor Who bosses are reportedly hoping that an actor of colour will take on the role for the first time.
Jodie Whittaker has announced she is leaving the role in 2022 after four years, alongside show-runner Chris Chibnall, and rumours have started swirling about who will replace her.
I May Destroy You star Michaela Coel, 33, is the front-runner to replace Jodie and become the fourteenth Doctor and the first non-white actor to take on the role.
A source said: "The team behind Doctor Who have always seen the sci-fi series as one of the most progressive shows on TV and this would only cement that."
The source added to The Sun: "It would be a momentous decision, particularly as in 2023 as the series celebrates its 60th anniversary.
"Producers now care less about the age or gender of whoever takes on the part than they do about this move — which would be real step forward for diversity."
But as Doctor Who currently doesn't have a show-runner for future seasons, talk about who will replace Jodie is all speculative at the moment.
Jodie began playing the Doctor in 2017, and was the first woman to take on the role.
She announced on Thursday she was leaving the show after three seasons alongside show-runner Chris.
Jodie said: "In 2017 I opened my glorious gift box of size 13 shoes. I could not have guessed the brilliant adventures, worlds and wonders I was to see in them.
"My heart is so full of love for this show, for the team who make it, for the fans who watch it and for what it has brought to my life.
"And I cannot thank Chris enough for entrusting me with his incredible stories.
"We knew that we wanted to ride this wave side by side, and pass on the baton together.
"So here we are, weeks away from wrapping on the best job I have ever had. I don't think I'll ever be able to express what this role has given me. I will carry the Doctor and the lessons I've learnt forever.
"I know change can be scary and none of us know what's out there. That's why we keep looking. Travel Hopefully. The Universe will surprise you. Constantly."
Jodie will star in a new series of Doctor Who later this year before exiting the show in a trio of specials next year.
The first special will air on New Year's Day 2022, the second will be later in the spring and the third, when the Doctor will regenerate, will air in autumn 2022 and as part of the BBC's centenary celebrations.
Jodie took over the role from Peter Capaldi, who played the twelfth Doctor from 2014-2017, with Matt Smith playing the eleventh from 2010 until 2013.
David Tennant had the role from 2005 to 2010 and Christopher Eccleston had the part for just one series in 2005.
Before the mordern reboot, the Doctor was played by a number of actors, including William Hartnell, Tom Baker and Paul McGann.
