Britney Spears says she is ready to ''quit'' pop music.The singer, who checked into Malibu's Promises rehab center in February, jokingly revealed her new album has proven so stressful she is considering a new career.

When Britney was asked when fans could hear her new LP, she smiled and replied: "I think I might be quitting!"

The "Toxic" singer, who is set to work with top producer Timbaland on her music comeback, was seen at the Millennium Dance Studio in North Hollywood undergoing a grueling two-hour dance rehearsal yesterday (April 11, 2007).

Meanwhile, Britney's ex-lover Justin Timberlake has been phoning her to offer a shoulder to cry on.

Justin, who dated Britney for four years before they split in 2002, was so concerned about Britney checking into rehab he contacted her.

He said: "I called her because I am worried about her. She is a great woman. I'm rooting for her. It seems like she is getting everything under control now."