Originally scheduled for an August 25 release date and then September 15, Mariah Carey's upcoming 12th studio album, "Memoirs of an Imperfect Angel," has been delayed yet again. "Memoirs" will now arrive two weeks later on September 29.

The singer has also pulled out of a string of appearances surrounding the album's release, including "VH1 Storytellers," the "Today" Show concert series, 2009 MTV Video Music Awards and her Hollywood Walk of Fame star ceremony.

According to a source at Def Jam, the label Carey is signed to, the reason for the delay is that the singer hasn't completed the album and needs to return to the studio to record additional songs.

A post on Carey’s official Web site, mariahcarey.com, today read: “Mariah is putting the finishing touches on her newest album, Memoirs of an Imperfect Angel, and we have shifted all of our TV and promo appearances to coincide with the new release date of September 29. We can't wait for the fans to hear the new album!”

Carey's latest single, "Obsessed," reached No. 11 on the Hot 100 chart and No. 15 on the Hot R&B/Hip-Hop Songs chart.