Britney Spears [ tickets ], who earlier this year had to scrap tour plans after injuring her knee, says she's going to remain on an indefinite hiatus.

"I know now that my knee gave out on me this past summer so that I would have no choice but to stop," she wrote in a letter to fans posted at her website. "My body was shutting down and needed rest."

The singer wrote that, rather than returning to work, she plans to "take some time off to enjoy life."

"I've actually learned to say 'No!'" her letter said. "With this newly found freedom, it's like people don't know how to act around me. 'Should we talk to her like we did when she was 16 or like the Icon everyone says she is?'

"Going and going and going is all I've ever known since I was 15 years old," she continued. "It's amazing what advisors will push you to do, even if it means taking a naive, young, blonde girl and putting her on the cover of every magazine."

Spears did manage to drop a subtle mention of her current single, a cover of Bobby Brown's "My Prerogative," into her announcement. "My prerogative right now is to just chill and let all of the other overexposed blondes on the cover of Us Weekly be your entertainment," she wrote. "Good luck, girls!"

The singer, who recently wed dancer Kevin Federline, added that "being married is great" and that she "can't wait" to start a family. She plans to use some of her time off for a honeymoon with Federline.

Spears' most recent album is last year's "In the Zone." In June, the singer suffered what a press release issued at the time described as "severe damage" to her knee when she fell during a video shoot. The injury forced her to cancel a summer tour of the U.S.