Britney Spears stripped off in the middle of an adult shop to try on raunchy underwear.

The 'Toxic' singer visited West Hollywood's X-rated Hustler Store and although staff told her she couldn't try on the lingerie, she lost her temper and whipped off her panties in front of shocked shoppers.

A source told Us Weekly magazine: "Staff employees told her they don't allow people to try on underwear.

"She looked out of it. There was nothing going on behind her eyes. She threw a fit and took off her underwear and tried on a pair of boy shorts with 'Barely Legal' stitched across the rear end in the middle of the store while 15 other customers looked on in astonishment.

"The employees kept saying, 'Don't change out here!' She's just like, 'Well, I couldn't take them in the fitting room!' It was like dealing with a child."

Britney's mood reportedly worsened when staff asked her to pay for the underwear, and she stormed out of the store snatching a wig as she left.

The 25-year-old singer is apparently obsessed with lingerie and adult toys. Her mansion allegedly boasts a secret double-locked X-rated "den of sin" complete with a mirrored ceiling, spanking paddles, whips, handcuffs and a closet full of "kinky outfits".

A source told America's Star magazine: "Britney is sexually obsessed. The 'Fantasy Room' is loaded with ticklers, whips, fur-trimmed handcuffs and much, much more. She wears Catholic schoolgirl uniforms, a maid's uniform and a Cinderella outfit."

Meanwhile, Britney has denied rumours she is pregnant for the third time.

It had been reported the star was expecting a baby with music producer J.R. Rotem, but Britney's assistant Sam Lufti has rubbished the allegations, telling Ryan Seacrest's radio show: "Don't know who made it up. J.R. doesn't even know what's up. It's fake. Completely fake. It's bulls**t. We just wrapped her video. Going home to sleep."

Rotem added: "There is absolutely no truth to this."