LOS ANGELES — Britney Spears is saying bye-bye to K-Fed.

The pop princess filed for divorce yesterday from her husband, Kevin Federline, who is a former backup dancer and aspiring rapper.

The Los Angeles County Superior Court filing cites “irreconcilable differences,” a court spokeswoman, Kathy Roberts, said.

Ms. Spears, 24, married rapper Kevin Federline, 28, in 2004. They have a 1-year-old son, Sean Preston, and an infant son who was born September 12. The divorce papers identify the baby as Jayden James Federline.

A message left with Ms. Spears’s attorney, Laura Wasser, was not immediately returned.

Ms. Spears married Mr. Federline eight months after ending a 55-hour Las Vegas marriage to her childhood friend, Jason Alexander. Her second marriage has provided endless fodder for tabloids, which have speculated frequently that the union was in trouble.

Mr. Federline’s attorney, Mark Vincent Kaplan, issued a statement declining comment.

“There is no statement at this time as requested by Mark’s client, Kevin Federline,” a spokesman for Mr. Kaplan, Michael Sands, said.

In the divorce papers, Ms. Spears asks for custody of the couple’s two children, with visitation rights for Mr. Federline. The filing lists as separate property, and thereby off-limits to Mr. Federline, “miscellaneous jewelry and other personal affects,” earnings, and other assets to be determined later.

The filing comes just a day after Ms. Spears, back in shape after the birth of her second child, made a surprise appearance on David Letterman’s “Late Show” in New York by popping up behind him as he was sitting at his desk.

Mr. Federline appeared in the movie “You Got Served” and performed as a backup dancer for Ms. Spears’s former boyfriend, singer Justin Timberlake. He was previously involved with actress Shar Jackson of TV’s “Moesha.” Mr. Federline and Ms. Jackson have two children.

Born in Kentwood, La., in 1981, Ms. Spears got her first taste of fame at age 11 when she joined the “New Mickey Mouse Club” TV show. Her fellow Mouseketeers included future superstars Justin Timberlake and Christina Aguilera.

Five years after leaving the show, she released her debut album, “Baby One More Time.” In the video for the title track, Ms. Spears dressed provocatively in a school uniform and cemented her reputation as a sex symbol. Yet, throughout a years-long romance with Mr. Timberlake, Ms. Spears always proclaimed her chastity.

By 2003, she had fully embraced her sex-charged image, sharing an open-mouthed kiss with Madonna during the MTV Video Music Awards.