Ariana Grande has called off her next Sweetener World Tour concert as she battles a "really tough" illness. The "Don't Call Me Angel" singer apologized to fans in an Instagram video after she canceled her Nov. 17 show in Lexington, Ky. The day prior, Ariana revealed that she'd been "very sick" ever since her last concert in London just over a month ago. "I don't know how it's possible, but my throat and head are still in so much pain … I just really don't know what's going on with my body right now," she wrote. The morning of the show, she told fans her pain had gotten "kind of 10 times worse" and that she was "devastated" to have to bow out of performing.