GiIllian Anderson and David Duchovny speak about the new X Files film, ' I want to believe'.
The new X-Files film has had its world premiere in Hollywood six years after the TV series finished.
The storyline surrounding I Want to Believe has been a closely guarded secret since filming finished in March.
David Duchovny, who plays Fox Mulder, says fans will find the plot familiar: "It concentrates more on Mulder and Scully's relationship."
The X-Files series ran between 1993 and 2002, with the first feature film, Fight The Future, released in 1998.
David Duchovny and Gillian Anderson filmed I Want To Believe in Vancouver, Canada, last Christmas.
A trailer for the movie shows their two characters, Fox Mulder and Dana Scully, looking for a body frozen in a lake with dozens of other FBI agents.
Duchovny, 47, says the relationship between the pair remains tense sexually.
"The relationship of the love story between Mulder and Scully is interwoven with this thriller," he said.
"It ties into the characters as part of the mythology and my character as a believer and Gillian's character as a sceptic and we butt heads in the way we always have."
Perhaps any earlier wouldn't have been the right time and it really felt like a reunion
Gillian Anderson on making a new X-Files film six years after the series ended
During filming, plot details for the new movie were kept under such tight wraps that, for a while, even David Duchovny didn't have a copy of the script.
But according to director, Chris Carter, it didn't affect the on screen chemistry between the two main characters.
He said: "It's always magical to see them, because it's almost as if time stops for them.
"When they look at each other, they share something that only they know. It's like they share a secret.
"There's a true warmth between them and we've all had our difficulties and we've all had our problems and it is a family. It can be a dysfunctional family.
"When I see them come back together it's always the same chemistry as Mulder and Scully."
The film was due to be made after the TV series ended in 2001 but Chris Carter says it took a lot longer than expected.
"We came up with the story and they said great and we negotiated everybody's contracts and all was working, then all of a sudden it came to a grinding halt, because there were business problems with the television show and contracts going backwards," he said.
"That ended up taking years to resolve. That's simply why we are doing it now."
Gillian Anderson is expecting her second child with Mark Griffiths
Since the end of the ninth series, David Duchovny's worked on another television series, Californication, while Gillian Anderson has appeared in Oscar-winning film, The Last King of Scotland.
Anderson says the years went by quickly, but the timing for a new X-Files movie was right.
She said: "Perhaps any earlier wouldn't have been the right time and it really felt like a reunion."
David Duchovny, Gillian Anderson and Chris Carter say they're all up for making a third instalment of The X-Files but the plans remain up in the air depending on the success of I Want To Believe.
The end of the movie has been left open just in case.
David Duchovny says the movie provides X-Files fans with a new case to get their teeth into.
He said: "I think that the closure at the end of the ninth year, I don't remember what it was, but it felt like an end.
"I knew we were ending the show so there was an end, but this is like a reinvigoration of my character and I think of the relationship between us."