Cheryl, Nadine Coyle, Nicola Roberts and Kimberley Walsh all reacted in different ways to the news on social media.
But each of the stars took advantage of their profile on social networks to support their former bandmate during this difficult time.
After forming in 2002, the five track hit the music charts and became one of the most famous girl groups in the world.
Although the group split in 2013, they all came together again to share their support for Sarah.
Cheryl simply posted a broken heart on her Twitter page on Wednesday when Sarah released the news.
The singer, 37, shared the unique emoji when she broke her silence on social media for the first time in months.
The Fight For This Love hitmaker didn’t feel the need to embellish his post with words.
It’s been three months since May, when The Greatest Dancer captain posted anything on Twitter.
Emotional Nicola admitted that she was “blinded” by the news of Sarah’s cancer battle.
The Masked Singer winner, 34, shared her heartbreaking response on Twitter to show her support for her former bandmate Girls Aloud.
Nicola reiterated that Sarah was “so loved and supported” during this difficult time in a heartwarming tweet on Wednesday.
She wrote: “It goes without saying that this is blind. @SarahNHarding you are so loved and supported. ”
Kimberley took to social media her heartbreak after the news broke.
The pop star valued Sarah’s strength and bravery in opening up her battle with cancer to the world.
Kimberley said she would be with her former bandmate every step of the way.
She wrote: “My heart is broken. You are so strong and courageous and we are with you every step of the way. ”
Her comment was posted under Sarah’s original Instagram statement.
Nadine declared her love for Sarah and reassured her that she would always be by her side throughout her fight.
Her gushing statement was filled with positivity about her former bandmate’s ability to “perform miracles.”
She wrote: “I love you !!!! You have always been able to work miracles when needed !!
“I am here all the way and always will be !!! ”
Nadine shared the post under Sarah’s Instagram photo from her hospital bed.
STATEMENT BY SARAH HARDING
Sarah bravely explained how she was diagnosed with breast cancer that had spread to other parts of her body.
She detailed how she had had weekly chemotherapy sessions.
Her full Instagram statement read: “Hello everyone, I hope you are all doing safe during this time of uncertainty. Haven’t posted here for so long, thanks to everyone who contacted me, it really means a lot.
“I think it’s a good time to share what’s going on. There’s no easy way to say that and in fact it doesn’t even feel real to write this down, but there you go.
“Earlier this year I was diagnosed with breast cancer and a few weeks ago I learned the terrible news that the cancer had spread to other parts of my body. I am currently on weekly chemotherapy and am fighting as hard as I can. can.
Sarah Harding’s courageous battle with cancer
“I understand that this can be shocking to read on social media and that it really isn’t my intention. But last week it was mentioned online that I had been seen in the hospital, so I think it’s time to let people know what’s going on. and that’s the best way I can imagine to do it. ”
My wonderful mom, family and close friends are helping me get through this, and I want to thank the wonderful doctors and nurses in the NHS who have been and continue to be heroes.
“I’m doing my best to stay positive and will keep you posted on how I’m doing. In the meantime, I hope you will all understand and respect my request for confidentiality during this difficult time.
“Sending all of you so much love… .xx. “