Sam Smith cancels iHeartRadio performance

Sept. 22 (UPI) -- British singer-songwriter Sam Smith canceled his scheduled set at Friday's iHeart Radio Music Festival in Las Vegas.

"Dear all, Due to unforeseen circumstances which transpired after rehearsal, it became clear that I'm sadly unable to perform at the iHeart Radio Music Festival in Vegas tonight. I am so so sorry about this and I want to apologise to all my fans. All my love, always. Sam x," Smith tweeted.

Variety cited unnamed sources as saying Smith had inexplicably lost his voice earlier in the day and hadn't recovered by show time.

Festival host Ryan Seacrest announced from the stage of the T-Mobile Arena that Smith would not sing as planned due to "unforeseen circumstances," but he did not elaborate.

"We love Sam. Sam has been part of our iHeart family for many, many years and we look forward to seeing him really soon," Seacrest said.