And with the New England Patriots winning the Super Bowl in historic fashion on Sunday night, you had to know something was coming from the Oscar-winning actor, who just happens to be a Boston native and big Tom Brady fan.
Kimmel began the segment by saying they had a special guest in the house.
"The most beloved Patriot of all," he said. "We are very honored he's here tonight. He could have gone anywhere, but I got a call late last night."
A man dressed in a No. 12 jersey stepped out on the stage and Damon looked away from Kimmel as he said, "I feel great, I feel like I'm going to Disneyland."
After a little chat between the two about Deflategate, among other issues, Damon as Brady made the joke, "This is happening. I'm on the Jimmy Kimmel show," alluding to the fact he can never get on.
"Why are you still in uniform?" Kimmel finally asked. "Take your helmet off."
Kimmel finally grabbed it off himself and pretended to be surprised when he realized it was Damon.
"I did it! Yes!" Damon yells. "If I'm not on the show right now, where am I? I'm on the show. Touchdown!"
There was an argument that ensued and security eventually escorted Damon off the stage.