David Duchovny thinks it is impossible Earth is the only planet hosting intelligent life.

The 63-year-old, probably best known for his role as FBI alien-hunter Fox Mulder in ‘The X-Files’ TV show and film spin-offs, stressed even though he thinks humans aren’t alone in the universe he does not believe extra-terrestrials are secretly in touch with us.

He said during a question-and-answer session for The Guardian when one if his fans asked: “Do you believe?”: “The proposition that Earth is the only planet in the universe that has managed to sustain intelligent life seems an impossibility.

“On the other hand, do I believe we’ve been contacted or are in contact with aliens?

“I don’t believe that, no.”

David added about the chance of returning to screens as Special Agent Mulder: “How often do I get asked if they are going to reboot ‘The X-Files’? I mean, that’s the default question people like to ask.

“If I was going to do it, I’d let y’all know. You wouldn’t have to ask me. I wouldn’t keep it a secret.

“Nowadays, I think people believe in conspiracies we never would have aired because they were just too stupid.”

David’s most recent film, ‘Reverse the Curse’, was directed by the actor and features him starring as grouchy father Marty, whose son Ted moves in with him as he battles terminal cancer.

He’s also recently published novels and is set to play the O2 Shepherd’s Bush Empire in London on 27 July and the UK’s Latitude festival on 28 July.

But David says one thing he has no intention of doing is returning to Yale University to finish his PhD.

The Hollywood veteran – who earned a Master of Arts in English Literature from Yale and began work on a doctoral thesis with the title ‘Magic and Technology in Contemporary Fiction and Poetry’ – said when asked if there was any chance of him finishing it: “That is a question my mother must have asked from beyond the grave. Where are you getting your questions from? A Ouija board?

“It’s not like you can just go blindly off and write a PhD dissertation. It would take two or three years of intense focus.

“The many things I’m doing, I’m trying to do well. If I added that into the mix, I’d probably screw everything up.”