The 43-year-old actor - who stars in sci-fi movie `Cowboys & Aliens` with Harrison Ford - is convinced extra-terrestrials life exists in the universe, but is unsure if otherworldly beings have ever visited planet Earth.
He said: "I do believe there`s life out there. I`m not sure I believe they`ve been to Earth but there is life out there."
Daniel, who recently married `Constant Gardener` actress Rachel Weisz, is not the only Hollywood star to believe in the existence of other life-forms.
`Avatar` actress Michelle Rodriguez has previously confessed to being intrigued by the possibility of life on other planets.
She said: "I believe in the possibility of aliens. We only perceive four per cent of what exists - the other 96 per cent is a mystery to us and to science, so I`m just leaving room for options.
"I can`t picture or imagine any aliens being as primal and destructive as humans. Jim Cameron has captured in `Avatar` and `The Abyss` what I believe aliens will be like if they exist."
Former Van Halen singer Sammy Hagar has also revealed his belief he was once abducted by extra-terrestrials.
He said: "That`s right. It was real. Aliens were plugged into me. It was a download situation. This was long before computers or any kind of wireless. There weren`t even wireless telephones."