Former Philadelphia Eagles legendary center and current ESPN analyst Jason Kelce made quite the debut on his first "Monday Night Countdown" appearance on Monday, September 9.

Kelce's NFL career solidified him as one of the best centers in the league. A seven-time Pro Bowler, six-time First-Team All-Pro, and a crucial figure in the Eagles' 41-33 Super Bowl LII victory over the New England Patriots, his legacy on the field is undeniable.

Known for his leadership, Kelce also helped guide Philadelphia to another Super Bowl appearance in 2023, where they narrowly lost 38-35 to his brother, Travis Kelce, and the Kansas City Chiefs.

While his playing days are over, Kelce has continued to entertain people off the field -- especially with his latest mishap on Monday Night Football.

After preparing for what was supposed to be a suit-and-tie moment on his big debut alongside Ryan Clark, Scott Van Pelt, and Marcus Spears, Kelce was the only one at the desk who had forgotten his jacket.

The Monday Night Football crew wasted no time poking fun at him.

"We are thrilled to welcome in a six-time All-NFL selection, a Super Bowl Champion, a future gold jacket wearer," Van Pelt teased. "And all that said, Jason Kelce is wearing a shirt he got from the mall because he left his travel bag in his truck."

Kelce stood there, soaking it in, visibly disappointed in himself but taking the blame. He had only a few words in response.

"It fits my belly," Kelce said with a smile, sporting a white Lululemon button-down. "I've lost a little bit of weight."

Since retiring, Kelce has been equally entertaining off the field, from his role on Monday Night Football to his popular "New Heights" podcast and other ventures, proving he's still a fan favorite even after hanging up his cleats.

Related: Jason and Kylie Kelce Reveal Little-Known Detail About Their Relationship