Janet Jackson goes on vocal rest, postpones shows

Janet Jackson isn't going to be singing for fans this weekend.

The performer tweeted that she's on vocal rest, "Doctor's orders," and has to miss her planned shows on Saturday in Salt Lake City and Sunday in Denver. The tour dates have not yet been rescheduled.

Jackson is in the middle of her Unbreakable World Tour, which has stops in the U.S., the U.K. and Japan through next summer.