Kelly Clarkson's highly anticipated Las Vegas residency opening was postponed hours before showtime because the singer needs vocal rest after demanding preparations.

There has to be some repercussion. Something for the people that spent thousands to get there,” one upset fan wrote via social media.

I am devastated to have to postpone tonight and tomorrow’s opening at Caesars. The prep and rehearsals have taken a toll on my voice,” she wrote in a statement shared on Instagram Friday.