By Fiona NimoniBBC News
Doctor Who star Jodie Whittaker is set to make her final appearance as the Time Lord.
She has led the show since 2017, and will end her time on the sci-fi series with a feature-length centenary special on 23 October.
In an episode titled The Power Of The Doctor, Whittaker will take on some of her deadliest enemies – including The Master, Daleks and Cybermen.
The actress announced she would be leaving the show in July of last year.
The episode will mark the first time all three of the Doctor's main enemies have featured in a single storyline since 2005.
Fans will see her try to work out who is attacking a bullet train in a distant galaxy and why 21st century seismologists are going missing from Earth.
A trailer released earlier this year revealed two companions from previous eras will be making an appearance.
- Former companions to join Jodie Whittaker's farewell
- Doctor Who: David Tennant and Catherine Tate to return
Janet Fielding will reprise her role as Tegan Jovanka – companion to the fourth and fifth Doctors,
Sophie Aldred – who starred as Ace, companion to the seventh Time Lord – will also be making a comeback.
The centenary special, to mark 100 years of the BBC, will also star Mandip Gill, Sacha Dhawan and comedian John Bishop.
Sex Education actor Ncuti Gatwa will take over from Whittaker to become the sci-fi series' 14th Doctor.
He will follow Sylvester McCoy, David Tennant and Peter Capaldi to become the fourth Scot to take up the role.
The 29-year-old, who was born in Rwanda, will also become the first person of colour to lead the series.
Speaking in May this year, Gatwa told the BBC: "It feels really amazing. It's a true honour. This role is an institution and it's so iconic."
A series of special episodes to mark Doctor Who's 60th anniversary will take place later this year.
David Tennant, the tenth Time Lord, will return to that show alongside Catherine Tate.