Hollywood actor David Duchovny has revealed the truth of what it was like to work with Sir Billy Connolly on the second of the two X Files feature films.

Duchovny, now 63, rose to worldwide fame as one half of Mulder and Scully in the hit 1990s TV show, which saw he and actress Gillian Anderson play FBI agents investigating paranormal activity.

The show expanded to two movies, one in 1998 and the second, in 2008, in which Scots comedian and actor Sir Billy played a disgraced priest.

Speaking exclusively to The Herald, Duchovny said Connolly was "as brilliant, as fast and as nice a person as he appears to be."

Filming for the movie often took place late into the night and Duchovny revealed the comedian had a unique way of making sure the cast stayed awake.

Connolly would improvise fake letters from fans of The X Files detailing how the Scotsman had ruined the franchise.

Duchovny detailed how, even at 3.30am, Sir Billy's voice would break a tired silence with the words "Dear Sirs..."

He said: "We'd be working all night or whatever, just sitting. Trying not to fall asleep.

"And he would always extemporaneously kind of compose a letter from a fan of The X Files as to why Billy Connolly ruined the franchise."

Putting on a fake Scottish accent, Duchovny added: "Dear Sirs, I must write about your second X File in which, unfortunately, Billy Connolly has ruined the franchise.

"It just went on and on.

"Always kind of like at 3.30 in the morning when there was quiet, he would feel the need to simulate.

"'Oh, Dear sirs'."

Duchovny also has a Scottish connection as his mother, Margaret, was from Aberdeen and emigrated to America to marry his father, Amram.

Duchovny added: "Well, I know Billy has been been ill and I hope he's feeling okay.

"I got a chance to work with Billy quite for a long time on the second X Files movie.

"And he was as brilliant, as fast and as nice a person as he appears to be."

Duchovny is touring Europe with his band and will be in Scotland on November 6 and 7, in Edinburgh and then Glasgow.

To read his interview with writer Catriona Stewart see here.