The singer insists she and her bandmates - who also include Cheryl Cole, Nadine Coyle and Kimberley Walsh - are always there for one another when they need support and all of them are ready to support Sarah now she has left rehab after being treated for alcoholism and depression.
Nicola told Seven Days magazine: "We support each other in everything we do and we are all there for her. Whenever any One Of Us needs an extra bit of TLC we are ready and we jump to the occasion, and Sarah is good, she's OK."
Nicola, 26, thinks she understand people very well and says if she wasn't a pop star she'd make a good psychiatrist.
She told Live magazine: "I'd make a good psychiatrist. I can work people out very easily and very quickly. I've been like that since childhood. I've always been a keen observer of people. In any social situation I'd much rather be on the periphery of things than at the centre. When I'm standing at The Edge I'm comfortable in my own skin. When I'm standing in the middle it's all confusion."