London (CNN) -- Singer George Michael has pneumonia and has been forced to cancel at least four shows, his website says. "He is currently receiving treatment," the brief statement says. His representative Connie Filippello told CNN the singer was "on the mend" and "receiving medication." She would not disclose information about where or when Michael had contracted the illness. Michael has postponed shows scheduled for this weekend in Cardiff, Wales, after putting off shows earlier this week in Vienna, Austria, and Strasbourg, France. He was also a no-show for a London concert scheduled for October 26. That concert is now scheduled for May 2, 2012, his website says. He said at the time he had thrown his back out. CNN's Stephanie Halasz contributed to this report.
NEW: Pop star George Michael is "on the mend," his representative says . The singer has pneumonia, he announces .