A mother always knows!

Jason Kelce’s shirtless antics during Sunday night’s playoff game between the Kansas City Chiefs and the Buffalo Bills came as no surprise to mom Donna Kelce.

Though the Philadelphia Eagle’s wife Kylie Kelce had warned him to be on his “best behavior” because they were meeting brother Travis Kelce’s girlfriend Taylor Swift for the first time, the beer-happy Jason went ahead and ripped his shirt off, let out a victorious yell and jumped out of the suite to celebrate one of Travis’ touchdowns.

Despite Kylie’s instructions that they “make a good impression” in front of Swift, Donna tells PEOPLE she knew “that wasn’t going to happen.”

“Jason’s his own man, as Travis is, and once they’re determined to do something, there’s no stopping.”

Donna tells PEOPLE she was “not at all” surprised by Jason’s “antics.” That’s because the Eagles center has “done it on occasion,” the football mom explains. “He just saves it for special moments,” she says with a laugh.

The NFL mom explained why her son’s shirt-removing gesture — followed by his decision to jump out of the suite to join the “Bills Mafia” in the stands — might’ve come as a surprise to many since “a lot of people don’t see it because he’s all business nine times out of 10 when he is on the field.”

“He’s so focused with the game and he’s so into it that people don’t see that side of him,” she adds.

But Donna says Jason is “just as lighthearted and as fun and as in the moment as Travis is” off the field. “It’s just, he is more businesslike when it comes to football.”

Travis shared a similar sentiment about Jason’s celebratory moves on Wednesday’s episode of their New Heights with Jason and Travis Kelce podcast. “Once a Kelce man’s determined there’s no f—ing stopping him,” Travis said.

The Chiefs tight end added that he wanted to see more of his sister-in-law’s reaction to the scene “so bad,” but “there was not enough cameras on the suite where you can see Kylie.”

Since the Philadelphia Eagles were eliminated from the playoffs after losing to the Tampa Bay Buccaneers on Jan. 15, Donna says that Jason “can finally let his hair down” now that he’s not playing.

While Kylie may have been less than pleased by her husband’s show, Swift loved it, according to Travis!

“[Your] best first impression is the worst impression ever,” the tight end said before sharing later in the podcast, “Tay said she absolutely loved you.”