Mel B spoke of her battle against the bulge and of how hard she had to work to lose all the weight gained during pregnancy.
The former Spice Girl, whose real name is Melanie Brown, was named the latest spokesperson for the Australia and New Zealand branch of weight loss program Jenny Craig towards the end of last year.
She has already succeeded in reaching her goal weight after losing 15 kg in just six months after giving birth to her daughter Madison.
The 36-year-old singer spoke about the struggles of shedding the excess weight in the glare of the public eye.
"You know what, it's not easy losing weight, and especially when you're doing it in front of everyone," Stuff.co.nz quoted her as saying on the Kyle and Jackie O Radio show.
"It's a bit embarrassing, but I kind of had to do it. I was fat!" she said.
Brown has posed on the cover of Australian tabloid magazine Woman's Day to show off the results of her exercise and diet regime and is thrilled with the results.
"The six-pack is back! I'm the same girl from 15 years ago ... losing weight has made me the best mum possible. My energy's up!" she told the publication.
She also revealed that she can now fit into her 13-year-old daughter Phoenix Chi's jeans.
"Well, the jeans were mine in the first place.
"She stole them off me when I was pregnant, but now I fit back into them. So I'm taking them back, one by one," she said.