Johnny Depp’s attorney Benjamin Chew has admitted he “lost [his] composure for a moment” when he was caught giving an excited fist-pump during the star’s explosive defamation trial.

Chew confirmed to Law&Crime that his now-viral courtroom celebration came because he knew Amber Heard’s decision to mention unfounded rumors about Depp’s treatment of another famous ex, Kate Moss, would be a turning point in unraveling her testimony.

“There was an instance in which Ms. Heard actually did admit to punching Johnny, and that was what we call the ‘staircase incident,” the now-celebrity lawyer told the outlet.

He recalled how Heard told the court she “had to punch Johnny” or else he would “have pushed her sister Whitney down the stairs the same way she had heard that he had pushed Kate Moss down the stairs.”

“I lost my composure for a moment and did a fist-pump because I knew that was not true,” Chew, 60, said of his caught-on-camera celebration.

Still, he insisted that Heard’s mention of the British supermodel “put a lot of pressure on us — we really had to come up with the goods.”

“Fortunately, Ms. Moss came forward — and this is a woman who has never testified, ever, for any reason,” he said.

“She wanted to correct the record, and she did so quite explicitly,” he recalled, detailing how Moss said Depp had never hit, kicked or pushed her during their three-year relationship.

It was “an important moment … because it debunked a defense to what otherwise appeared to be an instance of violence” by Heard, contradicting her long-held allegations of being the victim rather than the perpetrator of violence in their toxic marriage, he said.

Chew called the trial “so much fun” because Depp was “so funny.”

He choked up at recalling the moment they knew they’d won the case for the defamed star, saying, “It was emotional. I mean, we were so thrilled for him.”

He said Depp was “euphoric” when they spoke to him afterward. “He always looks great, but to me he looked 10 years younger,” Chew said. “I mean, it looked like the weight of the world was off his shoulders.”

Chew also noted the newfound fame aimed at him and his colleague, Camille Vasquez, who has since been made partner in her firm.

“For me, as a 60-year-old lawyer, [the newfound fame] was quite embarrassing,” Chew told Law&Crime.

“But it was very humbling, and really it was a reflection of the support out there for Johnny,” he said of the back-in-demand actor.