Nikki Blonsky's brawl with Bianca Golden surprised most people, but not everyone.
More specifically, a well-placed source alleges that Nikki's mother, Karen, has more often than not made working with her 19-year-old daughter unbearable.
The source was not shocked about the Turks and Caicos rumble between the Blonsky clan and former America's Next Top Model contestant Golden and her mom, Elaine.
"I'm just surprised it hadn't happened sooner," the source says. "Her mom is so obnoxious and difficult."
The source said the trouble started not long after Nikki was discovered in a nationwide search for an unknown pudgy gal to star as Tracy Turnblad in the Hairspray movie alongside John Travolta, Zac Efron and Michelle Pfeiffer.
Case in point: The source claims Nikki flaked out big-time on her promise to sing when she picked up an award at the Palm Springs Film Festival last year. "She said she would sing 'Good Morning Baltimore,' " the source said. "But at the last minute, she said she was too ill to perform."
And it apparently got worse. Nikki and her mom complained wildly about staying at the über-chic Parker Palm Springs hotel. "They didn't like the room," the source said. "The mother was in the middle of the lobby, bitching that she didn't like the food. She said she wanted to go check into a Hilton."
Here's the catch. Despite the moaning and groaning, the source said, "Nikki was well enough to jump into her chauffeured Town Car with her mom to go eat at places like Jack in the Box."
Hairspray costar Elijah Kelley stepped in at the last minute to sing at the film festival.
The source said that Nikki's publicist at the time quit on the spot or right after the festival. "Her publicist had had it," the source said. "She couldn't take it anymore because of the mother."
Shortly after the Turks and Caicos incident, Nikki's Hairspray costar and friend Brittany Snow came to her and her parents' defense.
"I don't know how it happened or what exactly went on, but my heart goes out to her, because I really do love her, and I know she didn't mean to hurt anybody—nor did her dad," she told People magazine. "Her family is amazing!"
Nikki's father, Carl, has been in a Turks and Caicos jail since his arrest after the airport smackdown. He has a court date this Friday and could possibly be released on bail.
Nikki and Bianca were also arrested on charges of assault.
Nikki's rep declined to comment.