"Brazil, I'm devastated that I'm not well enough 2 (sic) come to Rock In Rio.
I would do anything 4 u (sic) but I have to take care of my body right now," she wrote on Twitter.
The 31-year-old also didn't want fans in Brazil to feel disappointed by the cancelled performance.
"I ask for your grace and understanding, and promise that I will come back and perform for you soon," the 'Bad Romance' singer continued in a follow-up tweet.
She also posted a photo on Instagram of her arm with a needle in it and a tube running outside the photo's frame.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)