Britney Spears without knickers, getting into a carA friend of Britney Spears has explained that the popstar has stopped wearing underwear as “a joke on all of us”.

Tuesday Knight, a long-time friend of Britney’s, told In Touch magazine recently that she’s embarrassed at how the former teen star keeps exposing herself in public: “I love Britney - adore her - but she brings a lot of it on herself.”

“I’ve heard Paris Hilton, Lindsay Lohan and Britney talk about how they shock Hollywood just for the fun of it. They were discussing how they could play a little joke on all of us.”

“The underwear thing is ridiculous - and I’ve told her. I’ve said, ‘You cannot walk into a store wearing just a shirt with your underwear off.’ I’ve told her that no one will take her seriously when she does this.”

Tuesday explained that she was speaking out to show Britney how ridiculous it is - and causing people to focus on the wrong things: “Britney has always been a good mother. I want people to know that she’s the better parent - not Kevin!”

“Britney asked me, ‘Doesn’t anybody get to see this part of me?’ The answer is, no, they don’t. People just read about her not wearing underwear.”

“Britney doesn’t need to do it and she knows it’s stupid. But she says that she just doesn’t like to wear underwear.”