Time Lord thrills sci-fi fans at Comic Con.

It's one of the UK's biggest TV exports and stars of Doctor Who have come to talk to fans at Comic Con about the episodes that mark the end for the current cast line up.

The Wild West theme echoes the iconic 80's Back to the Future films.

But instead of being re-united in the right time dimension, the Doctor's assistant, played by Karen Gillan, will be separated from her hero for good.

(SOUNDBITE) (English) KAREN GILLAN, "DOCTOR WHO" CO-STAR, SAYING:

"I didn't stop crying for two weeks, in between takes. Anything was setting me off. Pictures set me off, broccoli, tender stem broccoli, anything. I didn't hold it together I've got to be honest."

Matt Smith will stay on as the Doctor. He's the eleventh incarnation of the eponymous Time Lord and is coming into his third season in the role but says he'll miss the chemistry he has with his fellow actors.

(SOUNDBITE) (English) MATT SMITH, "DOCTOR WHO" STAR, SAYING:

"If there's something happening in the scene and even now I might have to look and something's happened there like that and us three would go (the three of them look at each other at the same time) because you've become kind of symbiotic in a way. Because it's every waking hour of the day together and it's nine months and we film away from London and away from our friends. And we don't really argue, do we?"

It's the second time this Doctor Who team have appeared at the pop culture conference in California.

But if they make it back next year, fans can expect to meet a brand new assistant. She's a former member of the British soap, Emmerdale.

Jenna Louise Coleman will start her travels through time and space this Christmas.

Joanne Nicholson, Reuters.