Today, BBC America dropped a first-look video clip from the upcoming Doctor Who episode “The Girl Who Died,” guest-starring Game Of ThronesMaisie Williams. When it was first announced that Williams, aka GOT‘s Arya Stark, would appear on the show, it set dual fandoms buzzing. Nearly seven months later, the episode is afoot, premiering Saturday at 9 PM ET.

In the first of the two-part story, the Doctor (Peter Capaldi) and companion Clara (Jenna Coleman) must train a useless band of Vikings to defend themselves against the galaxy’s most deadly army. Williams plays Viking girl Ashildre.

Above is a clip of the episode and below a featurette in which Williams talks about those two fandoms colliding. Williams says she “didn’t know much about” Doctor Who, “but knew they were introducing a new character to work closely with the Doctor.” After watching two episodes, she “absolutely loved it!” and her agents worked “really hard” to get her the role. And when it was revealed she would be on the show “everyone lost their minds a little bit… When you crossover to another geeky fandom world, everyone’s like ‘this is insane!'”

“The Girl Who Died,” which some have speculated could refer to Coleman who is exiting the show this season, was written by Jamie Mathieson (Being Human) and lead writer and executive producer Steven Moffat (Sherlock) and directed by Ed Bazalgette (Poldark). The series is a BBC Cymru Wales production for BBC One and a BBC America co-production.