Prince’s security guards once had to pull Sean “Diddy” Combs off his girlfriend Cassie Ventura when he flew into a fury over her attending an exclusive party at the “Purple Rain” singer’s home, according to bombshell court testimony Thursday.

An ex-assistant of Combs’ detailed in Manhattan federal court how the Bad Boy Records founder became enraged when she and Ventura snuck out to Prince’s bash without his permission.

When the controlling music mogul showed to the fete at the legendary artist’s Los Angeles home sometime in 2011 or 2012, “me and Cass just booked it,” said the former staffer, “Mia,” who is testifying under a pseudonym because she’s an alleged sexual assault victim of Combs.

“He caught up to her and had her on the ground,” Mia testified.

“It’s like he started to attack her but Prince’s security swiftly intervened.”

His Royal Badness, who tragically died in 2016 from an accidental overdose, was first mentioned in Combs’ sordid sex trafficking and racketeering trial by Ventura during her explosive four days on the witness stand.

Ventura, 38, had testified that Combs beat her after the party — one of untold incidents of alleged abuse she suffered at the fallen billionaire’s hand during their fraught, decade-long relationship.

After Mia took the stand, she softly spoke about the “chaotic” and “toxic” environment working under Combs between 2009 and 2017.

“He’s thrown things at me, he’s thrown me against the wall, he’s thrown me into a pool, he’s thrown an ice bucket on my head,” Mia recalled. “He has slammed my arm into a door and he’s also … sexually assaulted me.”

Mia previously worked for Harvey Weinstein’s ex-wife and designer Georgina Chapman and comedian Mike Myers.

She testified that Combs wouldn’t allow her to lock her bedroom door when she started living in his home around 2009 or 2010 — a requirement not extended to his security guards, who were all men.

“Puff said this is my house, no one locks their doors,” she said.

Combs often physically attacked Ventura in front of Mia, including one time that left the R&B singer “gushing blood” from a cut on her face after he threw her against a bed, the ex-assistant testified.

During a trip in Turks and Caicos, Ventura and Mia found themselves fleeing from Combs twice, she told jurors.

The trio were on a trip in Parrot Cay in 2012 when Mia was awoken by Ventura one night “running and screaming.”

“You gotta help me, he’s going to kill me,” Mia recalled Ventura saying about Combs.

The two women barricaded themselves into a room, blocking the door with furniture as an irate Combs banged and screamed on the door to get inside, Mia testified.

The duo snuck out of a back door in the room and ran down the beach away from him, Mia recalled.

The pair had to flee from him a second time on that trip, when they laid flat on paddle boards off the shore while the Sean John clothing creator ran along the beach “screaming” and “irate,” Mia testified.

But the weather started to change while they were floating, Mia recalled.

“I was trying to weigh whether it was scarier to face Mother Nature or go back to Puff,” Mia said, noting they did eventually return to him.

Mia said she never reported any of the assaults to the cops because she believe that Combs “was above the police.”

The Prince party rampage resulted in a petty punishment for Mia, she testified.

She said she was told by Combs’ head of human resources that she was in “big trouble” and would be suspended without pay.

“She just said that Puff said I was being insubordinate,” Mia testified.

Combs, 55, has pleaded not guilty to sex trafficking and racketeering charges. He faces up to life in prison, if convicted.