Guess that’s just the way he rolls.

Former boy band member Kevin Jonas made a surprise appearance Thursday as a government witness in the FIFA international soccer corruption trial in Brooklyn — just so he could tell the court that he and his bandmates once saw a Beatle in concert.

Prosecutors called the “Burnin’ Up” musician to the stand simply to prove that a Paul McCartney concert had happened — because one of the defendants on trial is accused of having been bribed with $10,000 worth of tickets to the concert, in addition to millions of dollars in graft from sports marketers hoping to win exclusive contracts.

But as part of his defense Juan Angel Napout has refused to admit the show even happened.

Even defense attorneys were blindsided by the 30-year-old Jonas’ appearance.

“He’s one of the Jonas Brothers?” said a stunned Silvia Pinera-Vasquez, the attorney for Napout, a Paraguayan ex-soccer official. “Wait a second, my daughters need to know.

“My daughters are coming tomorrow, can I take a selfie?”she then asked shamelessly.

“If Mr. Jonas is willing to take a selfie with you, you can do whatever you want,” Judge Pamela Chen told her.

“There should be no sort of humor or drama,” interjected Assistant US Attorney Kristin Mace

Despite all the hubbub, Jonas was on the stand for just two minutes.

“I attended a Paul McCartney concert in Buenos Aires,” he testified.

“How was the show?” Mace asked him.

“Anytime you get to see Paul McCartney, it is pretty special,” he answered.

On cross examination by a flustered Pinera-Vasquez, Jonas said he’d been in the city for four days prior to the concert, and hadn’t gone to any soccer games.

“Like, did you open for Paul McCartney?” Pinera-Vasquez asked, before telling Jonas her daughters “follow” his band.

“No ma’am, he was performing. We got invited t the concert and we were just able to attend,” Jonas said.

“While you were there, you didn’t happen to run into my client, did you?” she asked.

“Not to the best of my knowledge,” he responded.

It wasn’t clear why prosecutors called Jonas, 30, and not Sir Paul himself.

Jonas also admitted he arrived late and missed the first two songs because “traffic is kind of bad with 85,000 people [going] to one concert.”

The Jonas Brothers performed at the same venue days later.

Before he left court, Judge Chen told Jonas to hang behind, saying: “You need to stay here so you don’t get stampeded.”

“He can go out the front door,” Pinera-Vasquez called out.

She later apologized for being “star-struck,” saying, “I quite frankly forgot the jurors were there, believe it or not.”

The attorney then mistakenly attributed the Fountains of Wayne song “Stacy’s Mom,” to the Jonas Brothers.

“I grew up with these. My daughters —is it, ‘Stacy’s Mom’ or whatever that song is. This is Stacy’s—”

She was then cut off by Judge Chen, and the trial continued.

Napout is on trial alongside ex-FIFA honchos Jose maria Marin and Manuel Burga, who are accused of taking millions in kickbacks from sports media and marketing firms.