The 'SexyBack' singer admits he would love to lift the lid on the pair's lengthy romance, including their sex life.

He said: "If I was writing an article about her, I would not be able to fight the urge to write every little dirty thing about her."

Justin, who split from the 'Toxic' singer in March 2002, also admits he still feels bitter towards his ex and doesn't think he ever knew the 'real' Britney.

The singer, who is now dating actress Cameron Diaz, said: "I dated Britney half my life. But I don't know that person any more. I'm not sure I knew her before."

Meanwhile, Justin's mother still misses her son's ex-lover Britney Spears.

Lynn Harless, who is also Justin's manager, has spoken out about how devastated she was when the young couple broke up in March 2002.

Lyn revealed: "Britney grew up on my living room floor. I still love her to death. Justin and Britney were together 10 or 11 years, and from day one they had that chemistry between them."

Lynn admits she is worried about the 'Toxic' singer and hates the constant negative reports claiming her marriage is in trouble.