Kimberley Walsh confessed she feels "completely helpless" while her former bandmate Sarah Harding fights breast cancer.
Her Girls Aloud bandmate Sarah went public with her cancer battle last year and she has been receiving treatment.
It has left Kimberley, who is pregnant with her third child, feeling "completely helpless" but she has been "constantly reminding" Sarah she's there to help.
She told Entertainment Daily : "With anyone who's suffering from cancer, that is the one thing you do feel is completely helpless.
"All you can do is literally be there, constantly remind them that you're there to help with whatever is humanely possible.
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"And she knows, she fully knows that, and that's all that I care about that she knows that she can ask us for anything."
Elsewhere in the interview, Kimberley praised her bandmate Sarah for being "amazing" and for focusing on writing a book.
The star said she has loved chatting about Girls Aloud memories with the band to help Sarah with her autobiography Hear Me Out.
All the Girls Aloud stars — Kimberly, Nicola Roberts, Cheryl and Nadine Coyle — have shown their public support for Sarah during her cancer fight.
Behind the scenes and on Instagram, they have united.
It has brought the group back together and they have stayed in touch through lockdown.
In recent weeks, Sarah updated her Instagram followers on her cancer fight.
She revealed she had finished writing her book in between visits to the hospital and treatments.
She wrote: "Hi everyone! I hope you are keeping safe and as well as possible with everything that’s going on.
"I know I'm not really that present on here which I promise I'll try to get a bit better at, as honestly it means the world to me when I come on and see all your well wishes.
"Thank you for the love and support, on bad days it helps me so much.
"So here's a little update from me... Mum, the dogs and I had a really lovely but quiet Christmas together, which was different to my usual, but seemed a fitting way to end such a strange year.
"And since then, in between treatments and hospital visits I've managed to finish my book!
"I can’t believe I've actually gone and done it and it's now at the printers! I'm so excited for it to come out."
