Mariah Carey celebrated Halloween with new billionaire boyfriend James Packer and soon-to-be ex-husband Nick Cannon.

E! Online reports the "Hero" singer rented a $15 million Beverly Hills property for the holiday party. Her twin 4-year-olds, whom she shares with Cannon, were also in attendance.

Word is the bash featured a huge dance floor, candle apple martinis for adults and fried mac and cheese for kids. Dressed as a witch, Carey wore a black leather dress with matching gloves, as she and Packer greeted guests including Tracey Edmonds and Jeff Beacher.

"Mariah and Nick got along great and were super friendly towards one another," a source said.

The two are now reported to be on much better terms than recently reported. Matters were growing more contentious between Carey and Cannon because of her desire to move in with Packer and relocate to his native Australia.

Several media outlets reported Cannon was staunchly against letting his kids move so far away and was even contemplating legal action as a last resort to prevent Carey from bolting. But now, all appears peaceful between the two parents.

"Nick is doing well in his personal life and he just wants Mariah to be happy," a source said. "He feels as long as his kids are in good hands, he will support any decision Mariah makes.

As for the party, twins Monroe and Moroccan came dressed as Batman and Batgirl, bagging plenty of candy as they went from home to home in the neighborhood.

Cannon came dressed as a zombie, while Packer kept things simple by donning a business suit and a "Phantom of the Opera" mask.