Kimberley Walsh is "devastated" by Sarah Harding's cancer diagnosis.
The Girls Aloud star has found it "really tough" that her bandmate is battling breast cancer but she has vowed to be there for her "every step of the way".
Speaking to The Sun newspaper, she said: "I am completely devastated, it's been really, really tough, but speaking to her a lot helps and keeping that contact. She knows we're there for her every step of the way.
"She's a strong girl and I love her so much."
Sarah announced the news of her cancer diagnosis on social media 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 the NHS "heroes" for their support and promised she'd "keep positive" amid her cancer fight.