Police sources have lifted the lid on what went on behind-the-scenes during last week’s craziness at Britney Spears’ L.A. home – and it’s not pretty.

According to insiders, the LAPD was faced with the sight of a topless Brit when they turned up at her Beverly Hills residence, following claims that she was holding her two boys hostage.

According to TMZ, the derailed pop star spent three hours locked in the master bathroom with her youngest son Jayden James, before emerging wearing nothing but panties.

When police tried to cover her with a sweater, she allegedly screamed: "Don't cover me up. I'm f**king hot."

The source claims that Brit's mood veered wildly between rage, tears and laughter.

At one point she is alleged to have raged at police: "What the f**k are you doing in my house?" and "I don't need your f**king help."

The singer's assistant, who was present during the stand-off, told officers that her boss had been "popping" "vitamins" all day.

Officers found a bottle of Prozac in her bedroom, say TMZ.com.

Her 'manager', Sam Lutfi, told officers he "knew this was coming for a long time," but didn't know how bad it would be.

Brit is expected to be questioned about these events during her court hearing later today - if she shows, that is...