She is to have an operation to remove cysts on her vocal chords, meaning she will not be able to perform at the event.
"I've been looking forward to it so much, it has always been a dream for me. I hope you all understand that if I didn't have to take out this damn cyst, I would have been there. But now I can't because I have to have the operation as soon as possible", she says in a statement.
Tove Lo released her debut album "Queen of the clouds" this year, and reached number three on the US Billboard chart, one of the best placings ever for a Swedish artist.