Back in March, BBC America announced that Game of Thrones actress Maisie Williams will be guest starring in a Season 9 episode of Doctor Who. While we saw Maisie Williams pop up in a recent trailer, we still haven't heard much about who she's playing in the beloved series. Today, the network has released a new trailer for this week's episode, The Girl Who Died, which gives us another look at her character, who, according to TV Line, is named Ashildr.

The episode centers on the Doctor (Peter Capaldi) and Clara (Jenna Coleman), who have been captured by Vikings. The Time Lord and his companion step up to help protect their village from Space Warriors from the future, known as the Mire. Outnumbered and outgunned, their fate seems inevitable. So why is the Doctor preoccupied with a single Viking girl? Presumably, Maisie Williams' Ashildr is this "single Viking girl," who may play a big part in the following episode as well.

The Girl Who Died, airing on Saturday, October 17, is the first of a two-part episode, which continues with next week's The Woman Who Lived debuting on Saturday, October 24. It seems possible that Ashildr will die in this week's episode, but could come back to life in The Woman Who Lived, but that's only speculation at this point. The actress is confirmed to appear in both episodes, so we'll have to wait and see how this intriguing story will play out.

Related: Doctor Who Showrunner Steven Moffat Leaving After Season 10

Other confirmed guest stars for Season 9 include Rebecca Front, Rufus Hound, Paul Kaye, Joivan Wade and Sophie Stone. The show's ninth season has been written by lead writer Steven Moffat, Toby Whithouse, Jamie Mathieson, Peter Harness, Mark Gatiss and new writers to Doctor Who, Sarah Dollard and Catherine Tregenna. This season will be directed by Hettie Macdonald, Daniel O'Hara, Edward Bazalgette, Daniel Nettheim, Justin Molotnikov, Rachel Talalay, and produced by Tracie Simpson, Derek Ritchie, Nikki Wilson and Peter Bennett.

In addition to this trailer, we also have a behind-the-scenes video where Maisie Williams talks about how Game of Thrones fans reacted to the news that she will guest star on Doctor Who. If that wasn't enough, we also have new photos from The Girl Who Died, before this highly-anticipated new episode airs on Saturday. Are you excited to see what Maisie Williams will bring to Doctor Who? Let us know in the comments after checking out these new videos and photos.

<strong><em>Doctor Who</em></strong> Season 9 Photo 1

<strong><em>Doctor Who</em></strong> Season 9 Photo 2

<strong><em>Doctor Who</em></strong> Season 9 Photo 3

<strong><em>Doctor Who</em></strong> Season 9 Photo 4

<strong><em>Doctor Who</em></strong> Season 9 Photo 5

<strong><em>Doctor Who</em></strong> Season 9 Maisie Williams Photo 1

<strong><em>Doctor Who</em></strong> Season 9 Maisie Williams Photo 2

<strong><em>Doctor Who</em></strong> Season 9 Maisie Williams Photo 3

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