Trump had said earlier that he has hired private investigators to look into the President’s birthplace.

In a NBC Nightly News interview with correspondent Brian Williams at the Tribeca Film Festival, De Niro stated that he believed the accusations to be without proof and unfounded. Many other celebrities are upset over the accusations including Jerry Seinfeld who pulled out of a charity event hosted by Trump’s son Eric.

Seinfeld said that he was becoming “increasingly uncomfortable” over accusations concerning Obama’s citizenship and nationality. Charlie Sheen also advised people against voting for Trump.

Trump is a possible contender in the upcoming 2012 Presidential race; he plans to make the announcement sometime in June.

Robert DeNiro Slams Donald Trump

The movie revolves around Thor, a powerful and arrogant warrior whose reckless actions begin a war. As punishment Thor is sent down to earth by his father to live among humans.

Thor is being played by “Star Trek” star Chris Hemsworth and Tom Hiddelston will star as his nemesis Loki. Natalie Portman will play Thor’s love interest, Jane Foster. Also cast in “Thor” are Robert De Niro, Jude Law, Jaimie Alexander and Colm Feore. Production is set to begin in January for a release on May 20, 2011.

Hopkins will next be seen starring alongside Benicio Del Toro in “The Wolfman” in February.

Anthony Hopkins to play Odin in The movie Thor