But Jimmy was quick to claim that the 46-year-old star's latest attempt to get on the programme wasn't a success because he didn't sit down on the couch, and was actually an "intruder".
Damon then appeared as Brady in full-uniform instead and attempted to give an interview as the National Football League star much to the audience's delight. "He flew all the way from Houston".
"Just haven't had time to change", Damon said.
The 46-year-old actor channeled Tom Brady as he made a surprise appearance on Jimmy Kimmel Live on Monday night. "I kinda don't want to ever take it off..."
The stunt was a reference to gag which has recurred since the third season of Jimmy Kimmel Live! in which the late-night host jokes he has to bump Matt as a guest on the show.
But Kimmel got suspicious after the athlete refused to remove his "lucky helmet", and, well... the ruse quickly came to an end.
Kimmel, disappointed, labelled Damon an "intruder" and had him escorted off the set.
It has to be tough for Atlanta Falcons fans right now, but Patriots fans around the country, including Damon, are finding their own ways to celebrate the fifth Super Bowl in the Tom Brady and Bill Belichick era. As the audience cheered, he added, "I'm on the Jimmy Kimmel show!"
Damon was then interviewed backstage by sports journalist Rich Eisen during which he gave a hilarious victory interview.