With the exciting first appearance of Varada Sethu in the third episode of Doctor Who Series 14, Boom, let’s take a look at everything we know so far about the new upcoming companion!
Sethu is currently filming for her first series on the show, and thanks to some leaked images circulating on X (formerly Twitter), we know that one of her episodes seems to take place in 1950s America; however, what is unknown at the moment is whether she is playing her character of Mundy Flynn from Boom, or whether she will be playing a different character altogether, similarly to Freema Agyeman who was cast as companion Martha Jones despite having previously appeared in the Series 2 episode Army of Ghosts as Martha’s cousin Adeola. On-location onlookers report the Doctor shouting a different name for the companion, though.
Her appearance in Boom has made her return even more exciting — does she really know the Doctor and Ruby or have they not met yet? Of course, following her guest appearance, fans have been speculating on who she might be — amongst the rumours of Susan and the Rani, as all mysterious characters have to be one of these two at any given time! Other theories include her playing an ancestor of Mundy; Mundy was actually a holographic AI; she is another “Impossible Girl” situation like Clara Oswald; or that she has been sent by River Song to keep an eye on the Doctor. All of these ideas and rumours are very out there and no doubt Russell will delight in reading them while keeping it a secret who she actually is.
Could she be someone to do with Mrs Flood? Or maybe she is another of Carla’s adopted children? We’ll have to find out in the upcoming series in 2025!

Sethu is no stranger to working with Doctor Who showrunner, Russell T Davies, having first worked with him on his 2016 television movie adaptation of A Midsummer Night’s Dream but she is also known for working on shows and films like Jurassic Park: Dominion, Annika, and Strike Back as well as having been a character in Andor, a Star Wars spin-off for Disney +.
So she is no stranger to science fiction, which’ll come in handy if any of the strange theories circulating the internet turn out to be true, but from our brief glimpse in Boom, she already shares a strong chemistry with leads Ncuti Gatwa and Millie Gibson.
And this actually makes them the first TARDIS team to be one Doctor and two female companions on screen since the Fifth Doctor travelled with both Nyssa and Tegan after Arc of Infinity. Of course, in the expanded media of books, comics, and audio adventures, we’ve had the pairings of Mel and Ace, Mel and Evelyn, Charley Pollard and Audacity, and Constance with Flip to name a few. But since 1982, the Doctor has either travelled with one male and female pairing or one solo companion or in the Thirteenth Doctor’s era, three companions. So it’ll be an exciting return to that dynamic and given her chemistry, she should make for a good fit.
Sethu has said that she already feels like part of the Doctor Who family and like one of the luckiest people in the world. We don’t know at the moment if she will be around for one series or will be staying for a couple, but we know that Ruby is rumoured to have a reduced presence in the next series.
Time will tell and I can’t wait to meet her character, whoever she may be, properly in Doctor Who Series 15!