[Flux]

The BBC officially confirms that Varada Sethu will become a companion in season 2 / series 15. Whilst the speculation was that Mille Gibson was sacked and Sethu replaces her, it appears they will both be onscreen together through the series.

www.bbc.co.uk 

Just to play devil’s advocate, it doesn’t say they’ll be on screen together through the series. Only that the Doctor will have two companions in Series 2.

They may well be, but the way it’s written it’s just as likely they’re only in a handful of episodes together, or even just the one episode which was being read on the day these pictures were taken.