India, July 6 -- S inger Kelly Clarkson abruptly postponed the opening night of her Las Vegas residency on Friday, announcing the decision just over an hour before she was due to take the stage. Kelly Clarkson: Studio Sessions - The Las Vegas Residency was set to kick off on July 4 at The Colosseum at Caesars Palace, launching the first of 18 scheduled performances running through November 15. In a statement posted to Instagram 90 minutes before showtime, Clarkson explained that intense preparations had left her unable to perform. "The prep and rehearsals have taken a toll on my voice," she wrote. "I want the shows to be perfect for y'all, and I need to protect myself from doing serious damage." She said she would be taking this weekend and the following week to rest her voice. "I am beyond grateful that you always show up for me, and I am devastated to have to postpone tonight and tomorrow's opening," she added. Clarkson assured fans that the show would be worth the wait. "The show is truly incredible. The musicians and singers are outstanding, and I want to start out strong. I can't wait to be back next weekend and show y'all what we have been working on," she said. So far, neither Clarkson nor the organisers have announced whether the cancelled shows will be rescheduled or if refunds will be offered to ticket holders....