Affleck, the star of Good Will Hunting and director of Argo, appeared on HBO’s television show Real Time with Bill Maher to promote his latest film, Gone Girl.
But instead of talking about the film, the 42-year-old found himself in a furious discussion with both Maher and Sam Harris, the author of a series of books on religion.
Maher, an outspoken atheist and critic of Islam, said last week in his show that “vast numbers of Muslims around the world believe that humans deserve to die for merely holding a different idea, or drawing a cartoon, or writing a book, or eloping with the wrong person.”
He said: “Not only does the Muslim world have something in common with ISIS, it has too much in common with ISIS.”
Mr Harris said: “When you want to talk about the treatment of women and homosexuals and free thinkers and public intellectuals in the Muslim world, I would argue liberals have failed us.
“The crucial point of confusion is we have been sold this meme of Islamaphobia – where every criticism of the doctrine of Islam is conflated with bigotry towards Muslims as people. Which is intellectually ridiculous.”
Affleck was angered by his comments, questioning Harris’ interpretation.
“You are saying that Islamaphobia is not a real thing?” he said. “It’s gross, it’s racist. It’s like saying ‘that shifty Jew’.”
Harris replied: “Ben, we have to be able to criticize bad ideas. And Islam at this moment is the motherload of bad ideas.”
Affleck looked shocked, muttering “Jesus Christ!” under his breath and sitting back in his chair. He then responded, telling Harris: “That’s an ugly thing to say.”
Maher backed up the author, telling Affleck that he was wrong to state that fundamentalist beliefs were only held by “a few bad apples”.
Affleck countered: “How about the more than a billion people who aren't fanatical, who don’t punish women, who just want to go to school, have some sandwiches, and don’t do any of the things you say all Muslims do?”
When Michael Steele, a political analyst, attempted to support Affleck, arguing that many moderate Muslim voices were not given the same amount of coverage as extremist ones, he was shouted down by Maher.
“It’s the only religion that acts like the Mafia. That will ------- kill if you say the wrong thing, draw the wrong picture or write the wrong book,” said Maher.
Affleck replied to his host: “Your argument is, ‘You know, black people, they shoot each other.’” Maher replied: “No it’s not! It’s based on facts!”
After ten minutes of fierce argument, Maher moved on – accepting that the panel would never see eye to eye.