United Kingdom, Oct. 7 -- Ben Affleck has admitted people are surprised to discover he's smart even after he won Who Wants To Be A Millionaire?

The 54-year-old actor, who co-owns production company Artists Equity with lifelong friend Matt Damon, won the top prize on the iconic gameshow back in July alongside Jeopardy! champion Jamie Ding.

Ben told GQ magazine's One More Question: "I recently went on Who Wants to Be a Millionaire? and won a million dollars.

"And I was telling somebody the texts I got are all kind of like. The underlying tone is one of slight bafflement. Like, 'How the f*** does this guy do that?' "

Ben's winnings were donated to Eastern Congo Initiative, the non-profit he co-founded with Whitney Williams in 2010 to sup...