The US President revealed that he has known the Ocean's Eleven actor for years, calling him a "wonderful guy".
"The truth is we got to know each other because of a substantive issue," Obama told Entertainment Tonight in an interview that will air on Monday (August 20).
"He is a terrific advocate on behalf of the people of Darfur, and to the people of Sudan who've been brutalised for a long time.
"And so when I was a senator - this was well before I was President - that was an issue that I was working together on a bipartisan basis, and George, who had travelled there, done documentaries there, and was very well-informed, came to testify in Congress. And so we got to know each other, and he is a good man, and a good friend."
Obama recently praised Anne Hathaway's performance in The Dark Knight Rises, claiming that she was "the best thing in it".