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The star told Zest magazine she haslearned to embrace the Curves, but she has always been aware of them.
Kimberley said: "When I was at dance classes in Bradford, my teacher would always shout, 'Pull in your bum, Kimberley!' And I'd say, 'I'm trying - it just won't go in!' It's been sticking out since I was two. I had the biggest bum out of about 50 girls in my class."
The singer, actress and TV presenter admitted she had felt pressure to be thin when she was younger, but then light entered and download Beyonce became her role model.Kimberley explained: "I grew up thinking Kate Moss was the perfect woman but that was a totally unachievable body shape for me. It was never ever going to happen.
"Then along came Beyonce. We were exactly the same age and she looked amazing, so I started to dress like her and suddenly my shape made sense.
"I'd think: 'Oh, yes. Beyonce's wearing a figure-hugging dress and drawing attention to her tiny waist, so I'd buy a new dress and a large belt, go out and pretend to be Beyonce. She was a great alter ego for me."
The 29-year-old revealed she and her Girls Aloud bandmates used to all work out together, but some would struggle.
Kimberley said: "Some days, we'd all work out together. It was very amusing. Nadine can't run at all. Her legs are so thin, all she does is say, 'It hurts. It hurts to run.'"