Stern offered the cash to anyone who could arrange for him to chat to Affleck, and was almost left speechless when the real deal called him.
Affleck explained he had heard the cash offer on the radio and decided to phone in, claim the money and give it to charity.
Saucy Stern started the interview by quizzing Affleck about his sex life - with fiancee Jennifer Lopez.
Candid Affleck confessed, "It's amazing, incredible, amazing," adding cheekily, "It's almost amazing as Paycheck, in theatres December 25th," plugging his new film.
The movie star also cleared up reports that his mother Chris disliked J.LO.
He told Stern, "My mother adores her, that's another common misconception."
And, as for his wedding plans, when Affleck was asked if he was going to get married in 2004, he revealed, "I certainly hope so, if I'm lucky."
Stern also managed to get in a quick question about Affleck's fabled night out with a stripper in Vancouver, Canada, this summer (03).
The DJ said, "Swear on your mother's life that girl is lying," prompting the actor to respond, "On the life of my future children and my mother. They paid that girl $200,000 (GBP117,640)."14/12/2003 10:41