
Doctor Who fans believe they have solved the enigma of new companion Ruby Sunday.
After making a brief cameo in the farewell special, Ncuti Gatwa’s Doctor made his debut appearance in the 2023 Christmas Day episode, bi-generating from David Tennant’s persona.
In it, he meets the cheerful Ruby (Millie Gibson), whose past is shrouded in mystery after she was abandoned on the doorstep of a church as a baby.
Ruby appears on Long Lost Family with Davina McCall in the episode, where the Big Brother star pledges to assist Ruby find down any relatives using genealogy and DNA testing.
When the findings are in, it looks like Ruby is all alone in the world, with no sign of a mother, father, siblings, relatives, or anything else.
The Doctor returns to the moment Ruby is left off at the chapel by a lady wearing entirely in black, her face hidden under a hood, and almost approaches to see who she is – but decides against it.
It’s evident that the mystery surrounding Ruby’s birth and why she was abandoned at the cathedral will play a significant role in the future season… However, fans believe they have already found it out.
Theories have been flying in thick and fast, with many agreeing that one in particular makes a lot of sense – or ‘sense’ in the manner that only Doctor Who can.
A lengthy discussion on Reddit over who Ruby may be and who might have abandoned her on the church stairs led to member Alex1081 guessing that the person going away is ‘Ruby herself.’

They suggested Ruby ‘finds her birth mother on an adventure (possibly not all human) who dies either in childbirth or shortly after. So Ruby and Doc take the baby Ruby and drop her off at the church to complete the loop.’
User Coraxxx agreed that they had the same thought ‘that it was Ruby herself. It has to be someone we know, given how much the camera focused on them, and the Doctor very nearly going up to them.’
On Twitter the same theory was making the rounds, with user Mike_J_Lord writing: ‘I can’t be the only one thinking that the woman who left Ruby outside the church was… an older Ruby. That would explain why there’s no DNA trace for her mother, she doesn’t exist yet!’

And Seanmelia123 agreed: ‘My prediction with ruby, the women who left baby ruby at the church is ruby herself she became some paradox because of whatever doctor who plot point so she’s stuck in a loop.’
And @wenbbilliams said they had ‘all kinda suspected the woman who left baby Ruby at the church is Ruby herself.’
There has previously been a narrative in which a character encounters themselves as a baby, but in this case it produced a tremendous paradox, with Billie Piper and Christopher Eccleston needing to save the world from destruction due to a tear in time.
However, as the bi-regeneration shown, the rules of Doctor Who may alter at any time, so keep an eye on this space.
Doctor Who returns in May 2024.