Nadine recently welcomed a baby girl with fiancé Jason Bell and Kimberly has only just announced her pregnancy with partner Justin Scott.
Sarah revealed that she was surprised at Nadine’s strong maternal instincts, saying that she thought having a baby might stress her out.
She said: ‘I’m amazed that Nadine has taken to it spectacularly, she’s taken to it like a duck to water.’
‘I thought all the responsibility would have stressed her out, but she’s so chilled. I can see Kimberley being a bossy mum, saying: ‘Get on the naughty step!’
Sarah couldn’t hide her excitement about the arrival of another mini-Girls Aloud star.
‘I can’t wait, one’s just popped out and another one is coming. I said to Kimberley: ‘My God, what’s going on?’And she was like: ‘I know, it’s the baby boom!’
Speaking to a UK magazine, Sarah also spoke about her own health problems and her issues with anxiety.
‘I suffer with ADHD, so I’m pretty hyper,’ she said.
The 32-year-old singer added: ‘I’m very isolated at home so when I’ve been away for a long time I get anxious. I’ve had panic attacks where I get a shortness of breath and I start feeling dizzy with a dry mouth and feel hot and cold. If I didn’t have my dogs to talk to in the countryside, I’d be talking to myself and going doolally.’