Evil, head-swapping robot King Hydroflax is played by a few people during The Husbands of River Song, with Matt Lucas, Phillip Rhys and Greg Davies all having the chance to find out why giving Artificial Inteligence the power to make life and death decisions is a stupid idea. But what about the robot itself? It did, after all, have a voice of its own, and behind that voice was none other than actor Nonso Anozie. 

Who? Well, you might recognise him better as Xaro Xhoan Daxos, the enigmatic merchant from series two of Game of Thrones. 

If you're a fan, then you'll remember that the last time we saw Daxos he was being sealed away in a vault – a punishment for betraying Daenerys Targaryen. Anozie's recent work also includes Cinderella, Atonement and The Grey and next year he'll appear in former Doctor Who showrunner Russell T Davies's adaptation of A Midsummer Night's Dream, playing Oberon. 

Anozie is not the first Doctor Who/Game of Thrones crossover, of course. In the past we've also had Harry Lloyd (Viserys Targaryen) in Human Nature/The Family of Blood, Diana Rigg (Olena Tyrell) in The Crimson Horror and – the big one – Maisie Williams' recent turn as the immortal Ashildr, to name but a few.