Spears: 'Federline taught kids to swear'

Britney Spears has accused ex-husband Kevin Federline of teaching their eldest son to say "f**k".

The popstar told Rolling Stone that she is shocked when she sees three-year-old Sean Preston, saying: "Every time [the boys] come to visit me, I think about how they're such special people. [But they] are starting to learn words like 'stupid' and Preston says the F-word now sometimes!"

She continued: "He doesn't get it from us. He must get it from his daddy. I say it, but not around my kids."

The 26-year-old, whose new album Circus lands on December 2, also revealed that her days of hard partying are behind her.

She said: "I feel like an old person now. I do! I go to bed at, like, 9.30pm every night, and I don't go out or anything."