BRITNEY PUTS MOTHERHOOD BEFORE PARTYING -- KIND OF!

New BFFs Britney Spears and Paris Hilton were slated to arrive in South Beach last Friday, and spend Thanksgiving weekend there partying it up with music producer Scott Storch — who is working on Britney's upcoming album — but Britney's maternal instincts kicked in!

"Britney was supposed to come to Miami on Friday, but [her son] Jayden had an ear infection, so they had to cancel," a source tells Star. "Jayden couldn't fly because of the ear infection, and Britney didn't want to leave him in L.A., so she scrapped the trip. She was waiting for him to get better, and was hoping to go, but she just decided to stay. She missed her flight on Friday, thinking she would get a later flight, but it never happened." The source adds that Britney and Paris, along with Jayden, were supposed to stay at Scott's place in Miami, and also record Britney's album at a Miami recording Miami studio. Plus, Storch was planning to take them to Walt Disney World on Saturday.

But Britney did get her fill of partying in, though, spending the weekend club-hopping with Paris. Well, it's a start!

Click here to see our photo gallery of Britney's wild weekend!

— DAVID CAPLAN