Ellen DeGeneres says there's a pretty good reason she was hanging with George W. Bush at the Dallas Cowboys game on Sunday ... they're friends -- and she's damn proud of it!
Cameras captured Ellen and Dubya laughing together in Jerry Jones' owner's box at AT&T Stadium ... leaving some people wondering why "a gay Hollywood liberal [is] sitting next to a conservative Republican president?"
Ellen says she took a lot of heat on social media from people who were angry over the affiliation .