Maisie Williams -- arguably the world's biggest star to those among us who continue to happily and unapologetically believe that "Game of Thrones" is the world's most important TV series -- is joining "Doctor Who." (There are also those among us who tend to believe that's maybe the world's second most important...)

 News just announced by BBC America -- it had been rumored -- and this will be for a "guest" role, so any suggestion that Arya Stark is leaving behind Westeros -- or technically Essos, because she begins the new season landing in Braavos, which is in Essos -- should not be even remotely entertained.

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Here are the statements:

Williams: “I'm so excited to be working on Doctor Who as it’s such a big and important part of British Culture. 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.”

Steven Moffat, lead writer and Executive Producer, added: “We’re thrilled to have Maisie Williams joining us on Doctor Who. It’s not possible to say too much about who or what she’s playing, but she 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.”

 Williams -- as you are probably now aware -- is one of the breakout stars of "GoT" and is currently filming "The Devil and the Deep Blue Sea," starring Jason Sudeikis and Jessica Biel.

 "Who" returns in the fall.