First they partied all night together, then they were feuding, then they reunited for Britney's birthday party.
But is Britney now taking aim at Paris Hilton, even threatening to blackmail her?
That's the wild rumor pitting the former party pals against each other. A new report claims Britney was fed up with Paris' supposed bad attitude toward Brit's closest friends and she decided to take action.
Brit, who turned 26 with Paris by her side last weekend, reportedly threatened the heiress with a sex tape showing her kissing another woman! She then supposedly sent a signed letter to Paris explaining that she'd better stop being "rude," or she'll release the tape on the Internet.
But today, Paris' peeps tell "Extra" the story is "not true."