The duo were teaming up to offer fans a "double best friend dinner date" for Ben's charity the Eastern Congo initiative and another NGO named water.org.
"It's great to be working with Matt again," said the Argos star. "It was a little awkward after he didn’t get the Robin role, so we couldn’t be more excited".
Matt and Ben made their offer through the website Omaze
Matt countered: "Yeah that was tough, but I still have the costume from my audition, so I'm hoping I can wear it when we meet the winners."
Explaining the offer, the father of four says: "You and a friend could win a trip to Los Angeles and stay at a four star hotel and be our very special guest at a very special Hollywood event."
His pal Ben adds: "It'd be like a best friend double date."
The friends parody their bromance in the video
Matt goes on: "Be like us hanging out, taking selfies and talking about how the Sox are doing" referring to the famous Boston baseball team.
"Or if you have more sophisticated interests," the Armageddon star interupts. "We could talk about 19th century literature or the current state of politics in the Middle East."
The Bourne Identity star then cuts in: "Or if you don't want to bored by Ben we could maybe switch it around and ask you some questions like: Where you from, what are you into, do you have any pets?"
The actors with Ben's wife Jennifer Garner
The game of one up manship continues, with Ben saying: "Or I could ask you more meaningful questions like: what are your hopes, what are your dreams, what are your fears?"
And Matt presses on: "And if like you don't want to get really weirded out by having existential questions posed to you by Ben Affleck then maybe we could talk about other fun stuff like stories from the set of The Bourne Identity or any of the other hit movies that I've been in."
"Or we could talk about stories from the movie Argo," his buddy interjects, adding with emphasis, "Which won Best Picture."
The pair's bromance goes back to their childhood when they grew up in the same Massachusetts neighourhood. They famously went on to win an Oscar together for writing the screenplay of Good Will Hunting.
That comes up when Matt says: "We could talk about Good Will Hunting. We could talk about who did the bulk of the writing - because I could answer that one."
The duo have been friends since childhood
Pretending to be incensed Ben blurts out that Matt is "incredibly short".
Taking the mock fight to a new low, he pokes fun at one of Ben's less successful films. " (We could talk about) the fact that Ben's left eye twitches every time you say Gigli.
Hurt Ben asks: "Why did you bring up the Gigli thing?"
Finally, Matt fires back: "I'm 5ft10 and a half. I mean if you take out Northern Europe I'm like way above the world's average."