David Duchovny has left X-Files co-star Gillian Anderson

"I was overjoyed that Ivan wanted me to do his movie because I wanted to do something completely different," said Duchovny, speaking in London on Tuesday.

"The X-Files and Evolution do both have aliens but Evolution is 180� from what I have been doing.

"And as far as I'm concerned, Mulder is not an issue. I just get on with being an actor and don't think about it."

Duchovny announced he was leaving the X-Files earlier this year, having been in the show since 1993.

On Tuesday he also added that he intended to bow out of the limelight altogether for the foreseeable future.

"I have been busy for eight years and I just want to take some time off and figure out what I want to do next," said the actor.

Bottom

In Evolution, Duchovny gets to crack endless jokes and be relaxed in a way that would have put Mulder in a cold sweat.

Reitman also allowed Duchovny and his co-stars Orlando Jones, Julianne Moore and Sean William Scott the freedom to improvise.

The aliens evolve at an alarming rate

In particular, one scene sees Duchovny down his trousers and do a "moony".

"It wasn't in the script it was impulsive. Just as you may use your hands to instinctly gesture, I just decided to use my ass!" he laughed.

Another attraction for Duchovny was bringing his own experience as a one-time teacher to the film.

"Teachers are usually portrayed as really strict but that was never my experience when I was a teaching assistant. I was keen to pass that on," he explained.

Down to earth

But despite his reputation for chasing monsters, Duchovny said he never took his work home.

He has been married to actress Tea Leoni, since 1997. She is soon to be seen in Jurassic Park III, surrounded by similarly vicious, computer generated creatures.

But, concluded Duchovny, away from the cameras the star couple have remained down to earth.

"We don't compare notes or consider what it must feel like to be eaten by a T-Rex.

"At home we talk about mundane things and discuss what we had for lunch."

Evolution opens across the UK on Friday 22 June.