Britney Spears threatens to release lesbian video of Paris Hilton.

Troubled pop princess Britney Spears has reportedly threatened her one-time pal Paris Hilton that she'll release video footage of her engaged in lesbian sex with a mutual friend, it has been reported.

According to British newspaper The Sun, the 'Gimme More' singer, 26, threatened to leak the tape, which allegedly shows the 26-year-old hotel heiress in a compromising position with another woman - unless Paris changes her attitude.

A source said: "The letter warns Paris that if she continues being rude to people, the footage will be leaked online."

The Sydney Daily Telegraph reports that Paris & Britney  fell out at Spears' 26th birthday parties in Hollywood last weekend.

Only yesterday, a message on Myspace added to the recent mystery surrounding whether Britney is pregnant or not.

The message suggested that the singer had suffered a miscarriage.

It read: "I don't really want to talk about it, but I will say that I have not been feeling well (cramps and spotting) for the past few days.

"I finally saw my doctor, and she said it was too late."