Sarah explained to her 215,000 followers that she had been diagnosed with breast cancer earlier this year and that the disease has since spread to other parts of her body.
She wrote alongside a picture of herself in hospital: “Hi everyone, I hope you are all keeping safe and well during these uncertain times. I’ve not posted on here for so long, thank you to everyone who has reached out to check in on me, it really does mean a lot. I feel now is the right time to share what’s been going on.
“There’s no easy way to say this and actually it doesn’t even feel real writing this, but here goes. Earlier this year I was diagnosed with breast cancer and a couple of weeks ago I received the devastating news that the cancer has advanced to other parts of my body.
“I’m currently undergoing weekly chemotherapy sessions and I am fighting as hard as I possibly can.
“I understand this might be shocking to read on social media and that really isn’t my intention.”
She continued: “But last week it was mentioned online that I had been seen in hospital, so I feel now is the time to let people know what’s going on and this is the best way I can think of to do so.
“My amazing mum, family and close friends are helping me through this, and I want to say a thank you to the wonderful NHS doctors and nurses who have been and continue to be heroes.
“I am doing my very best to keep positive and will keep you updated here with how I’m getting on.
“I am here for the all the way & always will be!!!”
Sarah’s post about her diagnosis comes after it was reported that she had stepped away from the spotlight back in March.
The singer was last seen in public at the National Film Awards in London in March 2018.
Sarah also stopped giving her fans regular updates on her social media accounts recently.