Nicola Roberts has been ''blindsided'' by Sarah Harding's cancer battle.

The Girls Aloud singer paid tribute to her former bandmate, who revealed on Wednesday (26.08.20) that she had been diagnosed with advanced breast cancer.

Alongside a number of heart emojis, Nicola wrote on Twitter: ''It goes without saying that this is blindsiding ... @SarahNHarding ... you're so loved and supported (sic)''

Meanwhile, Kimberley Walsh - who also appeared in the girl group alongside Cheryl and Nadine Coyle - admitted her heart was ''broken''.

She wrote below Sarah's post in the comment section: ''My heart is broken. You are so strong and brave and we are with you every step of the way.''

Sarah announced the news of her cancer diagnosis on both Twitter and Instagram alongside a picture of herself in a hospital bed.

She wrote: ''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. 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. (sic)''

Sarah also thanked NHS ''heroes'' for their support over recent months and promised she'd ''keep positive'' amid her cancer fight.