Kiefer Sutherland believes in aliens.

The 44-year-old actor thinks it is "arrogant" to suggest humans are the only form of life in the universe, and often ponders about extra-terrestrials when he looks up at the stars.

He said: "When I look up at the sky on a clear night and see the wash of stars and planets, and everything that is outside our universe, I have to believe there is life everywhere.

"It would be very arrogant to believe this is the only planet that could sustain some kind of life."

The Hollywood star - who appears in new movie 'Melancholia', which focuses on an apocalyptic Collision between Earth and a rogue planet -also revealed he likes to think about his own death, and often contemplates what he would do in a plane crash when he boards a flight.

He told the Metro newspaper: "I hope I would stand by my family to the bitter end. I think about that often when I am on the plane. If the plane goes down, how would I handle it? Would I scream just accept it, or try to do something about it?

"My hope would be that I would just be able to let go. There is something beautiful about being able to accept one's fate and just allow it to happen. We spend so much of our time fighting it, it would be nice to know that for a few seconds before it's all done, you would just let go."

Kiefer is not the only Hollywood star to believe in the existence of aliens.

Jodie Foster recently donated cash to the Search of Extraterrestrial Intelligence Institute (SETI) in California to help it continue its research work following US federal and California cuts to the budget.