Matt Damon, Jimmy Kimmel reignite decades-long feud: Watch

Matt Damon made a surprise appearance on Jimmy Kimmel's show, disguised as Frankie Focus, a new mascot promoting New York's school cellphone ban.

The "feud" between Kimmel and Damon started in 2005 when Kimmel ended an episode saying, "Apologies to Matt Damon, but we ran out of time," despite Damon not being scheduled to appear.

This playful rivalry has continued over the years, with both actors trading barbs and involving other celebrities like Ben Affleck, Sarah Silverman, and Tom Brady.

During the episode, Damon, dressed as Frankie Focus, asked Kimmel if he had a college degree, and when Kimmel replied he didn't, Frankie said, "I could tell from watching your stupid monologue!"

Kimmel eventually removed Frankie's head, revealing Damon underneath, prompting thunderous applause from the crowd.

Damon explained he wore the costume to get on the show, saying, "I know we've had our differences over the years, but I wanted to be here tonight for your last show ever." However, Kimmel corrected him, stating it wasn't his last show, and they have another episode scheduled for Monday.

The conversation took a turn when Damon referenced former President Trump's false claim that Kimmel's show had been canceled.

The actor joked, "But the president canceled you — which I was a big fan of, by the way." Kimmel clarified they weren't canceled but were off the air for three nights. Damon then asked if there was an appeals process, and after being told there wasn't, he swore, prompting Kimmel to ask, "You kiss your mother with that mouth?"

Damon responded by saying, "No, I kiss your mother with this mouth" and shouted out to Kimmel's mom in the audience.

As Damon exited the stage, he grabbed Kimmel's mom's hand and said, "Come on, Joan, come on. Let's let your little boy do his little show." Before leaving, he threw in one final jab, saying, "I was lying about the costume. It is a sex thing."

This latest exchange between Kimmel and Damon showcases their ongoing playful rivalry, entertaining audiences with their comedic banter.