TMZ reports that Grande told a handful of her friends that she was visiting Pete, and the friends gave Davidson a heads' up, prompting him to in turn alert his security.
The outlet also said that Davidson wouldn't come out of his dressing room Saturday during rehearsals, and he was therefore only given one line on the show, introducing Miley Cyrus.
Davidson has been open about his mental health struggles in the past, revealing he attempted suicide after he lost his father in 9/11 and suffers with borderline personality disorder.
If you or anyone you know needs help or advice, please call Lifeline (131 114) or Beyond Blue (1300 22 4636).
This article originally appeared on InStyle Australia