Britney Spears' wild partying is putting her music career in jeopardy.

The Toxic singer - who recently filed for divorce from husband Kevin Federline - spent every night of Thanksgiving weekend in Los Angeles partying until 6am with new best friend Paris Hilton and the late nights are taking their toll.

A source told the New York Post newspaper: "Britney has been missing recent recording sessions because she has been out all night partying.

"Her label, Jive, is very worried."

The 24-year-old star, who has two young sons, Sean Preston and Jayden James, has been telling her friends: "I gave birth for two-and-a-half years, and now I want to party."

Meanwhile, Britney has donated 170 personal items to an online auction at Christie's in aid of the Britney Spears Foundation for children in need.

Among the items is a page from her junior high school notebook containing her handwritten book report on Rex Warner's translation of Sophocles' Antigone.

The essay is expected to fetch up to $US700 at the auction, which takes place on December 4, and is written in black ballpoint pen on both sides of the paper.

Britney got 88 out of 100 for her efforts and gained comments from her teacher including "Nice" and "Organised".