Gillian Anderson won an Emmy TV award for The X-Files in 1997
Actress Gillian Anderson says filming her parts as Agent Dana Scully in the new X-Files film left her exhausted.
Filming for X-Files: I Want to Believe finished in Canada in March but the star, 39, says she struggled this time physically.
She said: "It was hard work. I'm too old for this. It was a slog.
"David [Duchovny], who's in the best shape of his life because he had to bonk people every two minutes for Californication, did most of the work."
She added: "He's climbing and jumping off cliffs. I didn't do any of that and I was more exhausted by the end of it than he was. I'm a wimp."
The X-Files ran between 1993 and 2002 on TV, with the first feature film, Fight The Future, released in 1998.
I Want to Believe is out in cinemas on 1 August and the storyline has been a closely guarded secret up to now.
But a new trailer for the film shows Fox Mulder (David Duchovny), Dana Scully (Gillian Anderson) and dozens of FBI agents looking for a body which is frozen in a lake.
It also stars rapper Xzibit and Scottish comedian Billy Connolly.
Gillian Anderson, who appeared in The Last King Of Scotland in 2006, says even she hasn't seen any footage yet.
"I'm doing ADR (replacing voices on a film) on Monday and that'll be the first time I've seen any footage of it whatsoever," she said.
"I'm excited and I hope it's good. I really hope it's good. I have faith in it. I do."
X-Files: I Want To Believe was filmed outside Vancouver in Canada
The actress is at the Cannes film festival to promote How To Lose Friends And Alienate People with Simon Pegg.
But there are posters up promoting the new X-Files film everywhere, something which makes the 39-year-old a bit uncomfortable.
She said: "It's so weird. When I think of Cannes I think of smaller films. And to see these blockbuster movies up there just seems so incongruous.
"And that I'm in one of them seems even more incongruous. It's a nice poster, I like it, it's very provocative."