Yes, that is Doctor Who’s new season 2 companion in Boom – but the mystery cameo leaves us with more questions than answers

Some spoilers for Doctor Who episode 3 follow. You have been warned. 

‘Boom’ was an instant classic: a nerve-shredding, landmine-stepping trip to a planet caught in the middle of a never-ending war.

Amid the chaos and tension, you may even spot a surprise familiar face. Among the very few characters with their boots on the ground (and in the mud) on Kastarion 3 is Anglican soldier Mundy Flynn, played by Varada Sethu.

Sethu is all set to be the Doctor’s next companion in the second season of the BBC/Disney Plus series. So why has she shown up early? Honestly, it’s not quite clear at this early stage. 

Doctor Who itself didn’t address it in the episode, save for a cute day-of-the-week quip from Ncuti Gatwa’s Doctor that she should marry Ruby Sunday (Millie Gibson) so they can be Mundy Sunday. 

There does appear to be a connection between the two companions present and future, though given the show hasn’t fully addressed the mystery behind Ruby and her snowy memories yet, there’s seemingly plenty of ground to cover before we bump into Varada Sethu again.

Moving forward, there’s probably going to be one of two outcomes: A) Varada Sethu returns as Mundy for reasons unknown as joins the TARDIS crew or B) Doctor Who pulls a ‘Clara’. 

The ‘impossible girl’ companion, played by Jenna Coleman, appeared twice as different iterations of the same character before joining the show full-time in 2013 – though her early appearance was part of a wider seasons-long narrative. 

Perhaps it’s the same again here. We’ll just have to be patient – the perplexing arrival of Mundy, it seems, is a story for another day.

For more, check out the best sci-fi movies of all time, plus Ncuti Gatwa, Millie Gibson, and showrunner Russell T Davies teasing every season 1 episode in a new interview with SFX.