Paris & Britney Split: Paris Calls Brit "The Animal"

They’ll always have Vegas! Paris Hilton and Britney Spears (who struck up an unlikely kinship in late November, following Spears’ separation from hubby Kevin Federline, 28) are on the rocks, and it looks like Spears, 25, was the heartbreaker.

Weeks ago, “Britney called Paris and said she had decided not to be seen in public with her ‘for now,’” a Hilton source tells Us.

Though the pair were once practically joined at the hip (they previously had a sleepover in Las Vegas and were spied dancing on banquettes at West Hollywood’s Hyde), things went sour after Spears took heat in the media for partying while leaving her two kids, Sean, 15 months, and Jayden, 3 months, at home.

“Britney told Paris that it’s not personal,” says an insider.

But beware a Hilton scorned. According to another source, the heiress, 25, didn’t invite Spears to her December 18 Christmas party and now refers to her ex-pal as “Animal.” Why?

“Britney doesn’t think about things before she does them. She just acts out,” says the source.

(Spears’ rep couldn’t be reached for comment. Says Hilton’s camp: “Her friendships are her own business.”)