The Doctor's new companion has been announced on the BBC's Children In Need show.

Coronation Star Millie Gibson has been revealed as the incoming co-star in an exclusive announcement during the broadcaster's annual appeal programme. 

Gibson revealed that her character will be called Ruby Sunday/ Sundae but would not confirm the spelling of the name on the fundraising spectacular.

The live BBC appeal show is one of the biggest fundraising nights of the year bringing together the biggest names in TV, including the likes of Ade Adepitan MBE, Mel Giedroyc, Graham Norton, Chris Ramsey, Jason Manford and Alex Scott MBE.

This year’s Spotacular campaign is raising funds to help tackle the effects the cost-of-living crisis is having on children and young people.

New Doctor Who companion revealed as Coronation Star Millie Gibson 

The official Doctor Who account had teased the news on Twitter on Friday alongside two red heart emojis and a red diamond. 

Fans rushed to the comments to speculate who might be joining Sex Education star Ncuti Gatwa on his adventures through space and time. 

One viewer suggested: "Companion or actor name is Ruby most probably."

Another user chimed in:" @RoseAylingEllis I’m still crossing my fingers it’s you! First deaf companion would be ICONIC!

A third person joked: "It's obviously Anne Diamond."

Other fans had shared theories that the 14th Doctor would be joined by fellow Netflix stars including Bridgerton's Ruby Barker or another Sex Education actor Mimi Keene who plays Ruby Matthews in the series.

The announcement comes after an emotional farewell to Jodie Whittaker's 13th Doctor in October in the feature-length special - The Power of the Doctor. 

BBC viewers were surprised as a familiar face reprised his role as the Doctor who originally played the Time Lord from 2005-2010.

READ MORE: Jodie Whittaker shares tip to new Doctor Who after regeneration on BBC special

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Since leaving the Tardis, Tennant returned as the Time Lord in the 50th-anniversary special 'The Day of the Doctor' in 2013.

He was also revealed to be reprising his role, alongside fan favourite Catherine Tate as Donna Noble for the 60th anniversary airing next year.

However, the beloved actor made a surprise return in the 90-minute epic as the 14th incarnation after previously playing the 10th Doctor.

The Scottish actor will return as the Doctor for three episodes in November 2023 as part of the celebrations alongside former showrunner Russell T Davies.

A brief teaser for the specials was released on Sunday and hints at the debut of Ncuti Gatwa, who will overtake Tennant as the 15th incarnation of the character.

His first episode is expected to air over the festive period in 2023.