Comedian Billy Connolly gets in touch with his serious side to play a priest in the new X-Files movie.

The Big Yin, 65, plays a priest of "dubious character" who appears to know "the truth" in the upcoming film The X-Files: I Want To Believe.

Connolly joins FBI Special Agents Fox Mulder (David Duchovny) and Dana Scully (Gillian Anderson) in the first X-Files story since the TV show ended in 2002.

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Spooky: Billy Connolly's character is at the centre of a dramatic, supernatural occurence

Connolly's role in the film is being kept under wraps by producers, but his repeated appearance in the film's trailer suggests he has a pivotal role.

The trailer shows Connolly's character leading a team of FBI agents to find something in the snow, declaring, "I know she's out there".

While producers of the film are keeping the plot line secret, they have promised audiences the film will be scary and will address Mulder's internal struggle with his faith.

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The truth is out there: Billy Connolly's priest character assists Mulder and Scully's investigation

Duchovny said: "It's very dark and frightening. We forgot, as we grew older and the show became so big, that it got so popular because it was that scary.

"This movie goes back to the original impetus of The X-Files, which is to scare the pants off people."

Producers have also teased X-Files fans by releasing images of Mulder and Scully seemingly about to embrace, stirring up the old will-they-won't-they storyline.

Duchovny has further confused X-Files fans by suggesting the intimate photo of the characters about to kiss was taken "as a joke".

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Will they or won't they?: A lingering moment between Special Agents Fox Mulder (David Duchovny) and Dana Scully (Gillian Anderson)

When asked if the agents finally move their relationship from professional to personal, director Chris Carter mused: "I would never say it was just a joke. The relationship does evolve.

"I know there was a planting of misinformation by producers. Therefore, it makes everything suspect, and I think that's a good thing."

The film also stars Studio 60 On The Sunset Strip actress Amanda Peet as Dakota Whitney and Pimp My Ride host and rapper Xzibit as an FBI agent.

The X-Files: I Want To Believe will hit British cinema screens on August 1st.

Taking the rap: David Duchovny's Mulder is assisted by rapper Xzibit's FBI character