Kevin Federline has been talking trash about Britney Spears’ new man, musician Howie Day.

“When Kevin heard they had a sleepover at her house, everyone wanted to know about it,” a source tells the new issue of Star. “He lit up a cigarette and said he guessed you have to head to the dump to find trash, referring to how Britney and Howie met while in rehab.”

Apparently, K-Fed isn’t the only one with a low opinion of Day. Spears’ new sweetie was arrested in 2004 for allegedly locking a fan in the bathroom of his tour bus when she rejected his sexual overtures, reports the tab. The next year, he was charged with verbally abusing a flight attendant while under the influence of alcohol and sleeping pills. He pleaded “no contest” to the fan incident, was fined and ordered to apologize; he served a year of probation for the episode aboard the plane.

“People have told Britney point-blank this guy has a permanent barstool in the Loser Lounge,” a friend told Star. “I was with her when one of her most trusted girlfriends told her, ‘You cannot let this guy into your life — after he gets a little publicity he will be gone.’ But when people say stuff like that, it’s music to Britney’s ears. She likes the drama.”