The 'Hard' singer sparked concern about her health after posting a photo on Twitter of herself hooked up to an intravenous drip. She also cancelled a number of commitments in the UK earlier this week.
Rihanna's father Ronald Fenty has now said that his daughter is not sick.
The Sunday Mirror quotes him as saying: "When I saw the pictures on Twitter I was worried like everyone else. But the truth is she was suffering from flu and exhaustion.
"She'd also lost a pound or two in weight and just wasn't feeling well. Even so, I sat her down and said she needed to take things easy. I told her it was important to chill out a bit, look after herself and not take too much on for a while… [A break] is just what she needs.
"Robyn is a smart, tough girl and is fine now. She has a good team around her and friends and family who will make sure she is okay."
Rihanna herself has denied claims that she is in poor health, saying the reports are "bull****".
Watch Rihanna and Coldplay's music video for 'Princess of China' below: