Celine Dion [ tickets ] has canceled five performances of her Las Vegas show, "A New Day ...," and an appearance at the Billboard Music Awards because of a what's described in a statement as a highly contagious respiratory infection.

"A New Day ..." shows scheduled through Dec. 3 at The Colosseum at Caesars Palace are canceled, and Dion is scheduled for a holiday break after that. Performances are set to resume Dec. 28th, according to a press release posted at her website. The Billboard performance in Las Vegas was scheduled for Dec. 4.

Doctors diagnosed the Grammy winner with mycoplasma bronchitis and gave her strict orders to stay home and rest, the statement said.

Those who purchased tickets with a credit card will be automatically refunded. Cash customers can get a refund or ticket exchange for a future show at the original point of sale. Those who made their purchase though Ticketmaster can call 1-877-4-Celine. (Ticketmaster is LiveDaily's parent company.)

Today (12/1), tickets went on sale for the final spring performances of "A New Day ...." The show, which kicked off in March 2003, is scheduled to wrap in 2007. It generally plays four to five times per week.

The Colosseum at Caesars Palace, which was built specifically for Dion's show, will host Elton John Jan. 30 through Feb. 17. Dion will return April 12 and currently has dates booked through July 1. The schedule is listed below.