Singer Mariah Carey [ tickets ] checked herself into a hospital on Wednesday night (7/25) due to "extreme exhaustion," and has canceled all upcoming appearances. Carey’s publicity firm issued a vague press release that did not further specify the nature of Carey’s ailment or her whereabouts.

"Carey has been hospitalized for extreme exhaustion after completing two movies, 'Glitter' and 'Wise Girls,' and simultaneously writing, recording and producing her album, the soundtrack 'Glitter,'" the statement said.

"She’s been working around the clock," spokesperson Cindi Berger said in an interview with the Associated Press.

According to published reports, Carey posted a recorded message to her official website before checking herself into the hospital. "What I'd like to do is just a take a little break or at least get one night of sleep without someone popping up about a video,'' Carey said. "All I really want is to just be me and that's what I should have done in the first place ... I don't say this much but guess what, I don't take care of myself." The message has since been removed.

Carey had been scheduled to headline MTV’s 20th anniversary party Aug. 1 at the Hammerstein Ballroom in New York, a show that will be broadcast live on MTV and MTV2. An MTV spokesman said the new headliner would be a "surprise--a surprise to even us." He added that MTV was informed of Carey’s cancellation earlier today.

Carey’s "Glitter" soundtrack, her first for Virgin Records, is due out on Aug. 21.

Last year, Carey was hospitalized in Boston for two days to recover from food poisoning.