Citing health concerns, singer Sam Smith says they will have to back out of upcoming performances.

Smith made the announcement after cutting a concert in Cape Town, South Africa short, in the middle of the show, due to vocal strain. Now he is cancelling upcoming shows in the near-future.

“In the wake of cutting his South African tour short last week, Sam’s medical specialists are requiring him to have further rest,” a tweeted statement by Smith reads. “Regrettably this means that he will be unable to perform at the Azerbaijan Gran[d] Prix in Baku this weekend or the Billboard Music Awards in Las Vegas next week. We apologize for the disappointment for those affected, but the primary focus at this time needs to be on Sam’s recovery and health.”

This isn’t the first time Smith’s voice has been an issue with the Billboard Music Awards. When he won top male artist in 2015, he accepted his award silently, holding up a card that said he could not speak and was resting his voice. Smith was forced to cancel several tour dates in 2015 in order to undergo and recover from surgery to repair a hemorrhage on his vocal cords, which occurred during a show in Sydney, Australia, according to Rolling Stone. Steven Zeitels, MD, the director of the Voice Center at Massachusetts General Hospital where the procedure took place, told CBS Boston at the time that Smith would be able to sing “more freely” after surgery.

Normani, who would’ve sung her track “Dancing with a Stranger” with Smith at the Billboards, released a statement, saying that she is “heartbroken” by the decision. “I have been working harder than I ever have in rehearsals for the last week to ensure that I give you the best possible performance,” she wrote. “I pushed my body in ways that I hadn’t in years, which I’m proud of, but unfortunately due to circumstances beyond my control, my performance at this year’s awards is not possible.” Normani thanked her fans and said she loved them “and Sam very much,” adding, “I am praying that he’s able to take the time that he needs. I’m with you.”

Other groups still slated to perform at the Billboard Music Awards include Taylor Swift, the Jonas Brothers, Madonna and Maluma, and Halsey with BTS.

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