'Doctor Who' Star Jenna-Louise Coleman Speaks, Quite Quickly, About Season 7 (Video)

Doctor Who formally introduces the series' latest companion during Saturday's season premiere -- though anyone at all familiar with the show should recognize her.

Jenna-Louise Coleman, Matt Smith's new partner in crime, has already appeared on the BBC America series as two different characters -- neither of whom fared very well. This latest role, Clara Oswin, is sticking around. And Coleman promises a resolution for the lingering mystery of her character's past incarnations.

"There's always this same essence, this spirit, throughout," Coleman said when she stopped by The Hollywood Reporter's Cover Lounge. "We will get payoff. It's a story to be eked out and teased throughout the arc of the season, in true Steven Moffat style."

The prelude to Coleman joining the series full-time has been a long one. It's been more than a year since showrunner Moffat confirmed she was to replace Karen Gillan and Arthur Darvill. And the audition process for the notoriously tight-lipped series required some finesse on her part.

"I kind of felt like a spy, having code names and secret phone calls with your agent," she says. "It's strange having a secret, but I only had to keep it for six weeks, thank goodness."

The decision to cast Coleman, it's been said, had something to do with her ability to speak as quickly as Smith -- and, in person, Coleman's cadence is suitably speedy.

"I suppose because you're always running toward something or away from something, the quick-fire dialogue is a big part of the show," she says. "ADR Is pretty difficult for me, to keep up with myself."

Doctor Who returns for its seventh season March 30 at 8 p.m. ET.

Email: Michael.OConnell@THR.com; Twitter: @MikeyLikesTV