An expectant Christina Aguilera has had to cancel two concerts in Melbourne, Australia, on the recommendation of doctors. Aguilera has been prescribed complete bed rest for the next few days as a result of a viral upper respiratory tract infection with a high fever and abnormal coughing. "I want to personally apologize to all of my fans for having to cancel my last two shows here in Melbourne," the singer said in a message. "Unfortunately, I have fallen ill with a bad flu virus." A number of tour staffers have also caught the flu bug.