Doctor Who season 15 showrunner Russell T Davies reveals how a major guest star made a return to voice the Fifteenth Doctor’s latest foe despite his previous appearance in season 11. In the second episode of the 2025 season, “Lux”, Ncuti Gatwa’s Fifteenth Doctor and new companion Belinda (Varada Sethu) arrive in 1952 Miami to try and return home to May 2025. However, the pair are suddenly pulled into a mystery when 15 people disappear in a theater, leading to them encountering a living cartoon named Mr. Ring-a-Ding who has stepped off of the screen.
As Davies opened up to Doctor Who Unleashed about the latest new addition to the show’s gallery of villains, the showrunner touched on why they cast Alan Cumming as the voice of Mr. Ring-a-Ding, the latest vessel of Lux, the God of Light. While Davies was hesitant to bring him back to the series only three seasons after his last appearance in “The Witchfinders,” the showrunner later realized that the actor’s performance was too perfect to pass up for the chaotic cartoon, with him only having a voice role lessening any fears. Check out Davies’ full explanation below:
“That was a great process with Alan Cumming, because he’s so perfect and so obvious, but he has done Doctor Who before, very recently in The Witchfinders. We kind of had a momentary pause over it for that, but then we just thought, he’s so perfect, and he’s not actually in vision of this. I think if it was Alan Cumming standing there, being a creature, that’s a bit too soon. But because it’s just a voice, I mean he’s so skilled. That’s the thing about Alan, is that he knows what a villain is, he knows how to pitch things, he knows what’s funny, he knows what’s serious. He knows what’s sinister. And that’s a skill you just want on your side, so it’s brilliant, I’m so happy.”
What The Cumming Casting Choice Could Mean For Doctor Who’s Future
The Production Is Becoming More Flexible With Its Casting Choices
Davies’ era of Doctor Who has relaxed many previous practices that some viewers may have formerly held in great esteem. This includes taking a more flexible response to canon by stating the universe has been radically altered. As such, while there are some cases where a returning star’s multiple roles may be explained through lore, such as Belinda’s connection to Sethu’s season 14 character Mundy Flynn, others are less heavily thought about. There has been a noticeable trait shared between the three returning guest stars of Davies’ current showrunning tenure, however.
In his recent tenure, Davies has cast five former Whoniverse stars in new roles: Cumming, Miriam Margolyes, and Indira Varma in the main series, and Gugu Mbatha-Raw and Russell Tovey for The War Between The Land and Sea. While they may be returning to the Whoniverse, their new roles have tended to be incredibly far removed from their past roles, either by their place in the timeline or playing new species where they’re less recognizable due to being in heavy make-up or through providing voice roles. As such, any future returning guest stars will likely follow this trend.
Our Thoughts On Cumming’s Doctor Who Return
The Actor’s Performance Was A Perfect Fit For Davies’ Faction Of Deities
Cumming’s portrayal of Mr Ring-a-Ding was undoubtedly worth any risk that Davies and the other Doctor Who producers may have been worried about, as the actor gave the latest addition to the Pantheon of Gods a personality that perfectly fit alongside their celestial family members. As such, Lux was able to emerge as one of the current era’s best new villains. With Davies becoming more open to allowing former guest stars the opportunity to dive into a new corner of the Whoniverse, many may ponder which guest stars they’d like to see return to the series in a new light.
Source: Doctor Who Unleashed

Doctor Who
- Release Date
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December 25, 2023
- Directors
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Douglas Camfield, David Maloney, Christopher Barry, Michael E. Briant, Barry Letts, Michael Ferguson, Richard Martin, Peter Moffatt, Pennant Roberts, Lennie Mayne, Chris Clough, Ron Jones, Paddy Russell, Paul Bernard, Michael Hayes, Timothy Combe, Morris Barry, Gerald Blake, Graeme Harper, Waris Hussein, Rodney Bennett, Mervyn Pinfield, Hugh David, John Gorrie
- Writers
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Russell T. Davies, Dave Gibbons, Kate Herron, Steven Moffat
- Franchise(s)
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Doctor Who