She informed her fans that she had advanced cancer, which had spread to other parts of her body.
Sarah has been inundated with support from her Girls Aloud bandmates after she shared her health news.
Kimberley Walsh said: “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 humanly possible.”
Speaking to Entertainment Daily, Kimberley shared how she and the rest of the band are trying to be there for Sarah.
“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.”