Maisie Williams, Arya Stark in 'Game of Thrones,' to guest star on 'Doctor Who'

LONDON, March 30 (UPI) -- English actress Maisie Williams is momentarily trading Westeros for London as she is set to make a guest appearance on the cult show Doctor Who.

Williams, best known for playing Arya Stark in HBO's Game of Thrones, was in Cardiff last week shooting scenes from her forthcoming guest role in the long-running BBC sci-fi thriller, which will air later this year.

"I'm so excited to be working on Doctor Who as it's such a big and important part of British culture," Williams said according to The Guardian. "I can't wait to meet the cast and crew and start filming, especially as we'll be shooting not too far from my home town."

Docto Who producer Steven Moffat says Williams' character "is going to challenge the Doctor in very unexpected ways."

"This time he might just be out of his depth, and we know Maisie is going to give him exactly the right sort of hell," he added.

Williams will reprise her GoT role when the show returns for its fifth season on April 12.