The 36-year-old Australian singer and TV presenter, who is currently a judge on reality series The X Factor, said that she wanted to feel "strong and sexy" again after giving birth to daughter Harper 13 months ago.
Bassingthwaighte told OK! magazine: "I feel really good now. It's taken... 13 months. I wanted to look the best I've ever looked and, about two months ago I started training. I feel like I actually put in effort this time and I'm really happy with the results.
"In my head I was like, 'I want to do it one more time. I want to stand up there in my little hotpants and shake that booty - that little bit bigger booty.' I think all women who have children want to feel strong and sexy like we might have before and yeah, I do - I feel better than ever."
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Bassingthwaighte revealed that she toned her body with boxing, interval training, sprints and Tracy Anderson's exercise DVD. She added that her sister was her "inspiration", because she took up running a year ago after never working out and looks "amazing".
The star described her life as "madness" at the moment as she juggles The X Factor, motherhood and planning her wedding to former Rogue Traders bandmate Cameron McGlinchey.
Bassingthwaighte said of her partner: "Not a day goes by when I don't feel like I'm the luckiest person in the world to have met Cam. He's just amazing."
Watch Natalie Bassingthwaighte's 'Someday Soon' video below: