Jenna Coleman said the upcoming "Doctor Who" 50th anniversary special is going to be both celebratory and transformative.
"The whole episode is a massive celebration and it's kind of about celebrating the last 50 years of 'Doctor Who,' with a massive team of us all thrown in there, but it's quite a transformation episode and it very much changes the direction of where the show is going in quite a big way," Jenna told Access Hollywood on Thursday in Beverly Hills.
Jenna and her Doctor - Matt Smith - have wrapped filming the episode, which features David Tennant, John Hurt and Billie Piper.
"It's in the can and all the 3-D and effects and everything like that is taking place as we speak," she told Access.
The last episode of Season 7 of "Doctor Who" introduced John as "The Doctor," and Jenna continued to tease the mystery of how he fits into the fold.
"He is the Doctor that no one knew about. He is the Doctor that's never talked about, not mentioned and of course were going to explore why and that stor,y and also see David's Doctor and Matt's Doctor and John's Doctor - the three of them interacting, which is great," she said.
As fans of the BBC America series know, Matt is leaving "Doctor Who," and Jenna said she's trying to enjoy their time together while she can.
"It's kind of unimaginable for me at the moment, but as I say the new Doctor isn't yet cast and my head is -- we're just having great fun together and enjoying the time we have left," she said. "It's a strange thing because I always knew he was gonna be leaving so it will be kind of bittersweet. But I think possibly there's quite a bit of denial going on."
The "Doctor Who" 50th anniversary special will air November 23 on BBC America.
-- Jolie Lash
Copyright 2013 by NBC Universal, Inc. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.