Maisie Williams to be new character on 'Doctor Who'

BEVERLY HILLS, Calif. - When viewers see Maisie Williams on the new season of "Doctor Who," she'll be a brand-new character, not one from the past.

"Once you see what she's up to ... you'll appreciate what a clever idea it was," show runner Steven Moffat said Friday at a TV critics panel. "It's a significant role. We're not just getting star value and throwing it away. It's a great part, and she's terrific in it."

Williams is best known as Arya Stark on HBO's "Game of Thrones," and Moffat says her role on "Doctor Who" is different for the 18-year-old actress.

"If people are hugely associated with a much-loved show, then it's good to have them on your show. The audience is clever. They know you're playing somebody else. They don't get confused," he said.

Moffat also teased that "it will take you a moment or two to realize what we're up to" with Williams' character.

Season nine of "Doctor Who," which stars Peter Capaldi as The Doctor and Jenna Coleman as his companion, Clara, premieres Sept. 19 on BBC America.