Who is Ruby Sunday? The Doctor Who companion explained

The Doctor Who Christmas special, ‘The Church on Ruby Road’, introduced Millie Gibson’s Ruby Sunday — here’s everything you need to know about the Doctor’s new companion.

It’s worth noting Ruby wasn’t the only fresh face in the Christmas special. The festive-themed adventure also marked the Fifteenth Doctor’s proper debut before the new Doctor Who episodes, following his introduction in the final Doctor Who 60th anniversary special, ‘The Giggle’.

The Doctor without a companion is hardly a Time Lord at all, and Ruby Sunday was his first time-travelling partner throughout this new era. As a young woman with a mysterious past, Ruby brings and drama to Doctor Who Season 14.

Here’s everything you need to know about Ruby, where she comes from, and how long she’ll be in the show for.

Who is Ruby Sunday in Doctor Who?

Ruby Sunday is the Fifteenth Doctor’s companion, played by Millie Gibson, who was introduced in the Doctor Who 2023 Christmas special and was abandoned by her mother as a baby.

Ruby’s infant abandonment brought some mystery to the show, especially since the question mark around the identity of her mother formed most of Season 14’s arc.

At first, all we knew about Ruby’s past was that she was left on a church doorstep as a baby on Christmas Eve. The Doctor Who Christmas special further established that Ruby’s name is derived from the church itself, which was situated on Ruby Road.

‘The Church on Ruby Road’ also revealed that Ruby was adopted by her foster mother, Carla (Michelle Greenidge). When the special kicks off, 19-year-old Ruby and Carla are living in Notting Hill, along with Ruby’s grandmother, Cherry (Angela Wynter).

In an interview with SFX, showrunner Russell T Davies hinted this puzzle would play out over Doctor Who Season 14.

“Not every question is answered in the Christmas special,” Davies teased. “And that continues all the way through to the most magnificent finale ever shot on planet Earth. No hype! I swear that’s true.”

Ruby is a feisty Northerner, who has a real sense of awe and wonder about her time-travelling adventures. But her life is always bookmarked by her sadness over not knowing her birth mother, a fact which often causes her great distress.

How does Ruby Sunday meet the Doctor?

Ruby Sunday first encounters the Fifteenth Doctor in a London nightclub where they share a brief exchange, during which the Doctor hints that Ruby’s recent bad luck is more than it seems.

The pair stay strangers at this point (although the Doctor does wish Ruby a “Merry Christmas”). The Doctor and Ruby’s formal introduction comes later in the special, while they’re chasing after baby-snatching goblins.

Dangling precariously from the goblins’ airship, the Doctor and his soon-to-be companion finally swap names and quickly form an effective partnership. Indeed, it’s hardly surprising that when the special ends, Ruby joins the Fifteenth Doctor on his next adventure.

Who is Ruby’s mother?

Ruby’s mother is revealed to be an ordinary woman named Louise Allison Miller in the Doctor Who Season 14 finale, ‘Empire of Death’.

Since the majority of fans assumed that Ruby’s mother would be some major or supernatural figure (which is fair, considering the show kind of told us that’s who she would be), many fans were very confused to find that she was, essentially, no-one.

But as the Doctor tells Ruby: “She’s important because we think she’s important.”

Ruby later tracks down Louise and meets her for the first time in a coffee shop, where the two embrace. We also later see Louise with Ruby and Carla in their home, where the new family all have dinner together. It’s a happy ending, at least!

For more, check out our full breakdown of Ruby Sunday’s mother.

How long will Ruby Sunday be the Doctor’s companion?

Ruby Sunday will only be the Doctor’s main companion during Doctor Who Season 14, though Millie Gibson will reprise her role in Season 15.

At first, it was believed that Gibson would be leaving the show after Season 14 and would be replaced by Varada Sethu. However, it was then confirmed that Gibson would be appearing as Ruby in Doctor Who Season 15, alongside Sethu as the Doctor’s second companion.

This means that Ruby could be involved in a smaller capacity, which makes sense, since her biggest mystery has now been solved.

Doctor Who Season 14 is now streaming on BBC iPlayer (UK & Ireland) and Disney+ (everywhere else). For more, check out our thoughts on the first two episodes with our ‘Space Babies’ review and ‘The Devil’s Chord’ review.

We’ve also got guides on all the Doctor Who Season 14 villains, as well as explainers on Mrs Flood and Susan Twist!