Ciara lost 60lbs in four months by working out with Khloe Kardashian's trainer.
The 29-year-old singer enlisted Gunnar Peterson to help her lose weight after giving birth to son Future last year and she could not be happier with the results.
Ciara told Shape magazine: "Five days a week, Gunnar puts me through an hour-long plyometric cardio circuit that always includes boxing elements. It's hitting your muscles; it's a cardiovascular workout; and it's a mental exercise... After I've done a few rounds, I feel as if I can conquer the world."
But Ciara also put in extra hours in the gym on her own and overhauled her diet.
She explained: "I would go to Gunnar first for my one-hour training session, then I'd have two more cardio sessions later in the day. That, along with a really clean eating plan, was how I lost 60 pounds in four months.
"I also believe that drinking tons of water and flushing out your system is crucial for training. It really helped me drop the weight. I tell myself that water is my medicine and that to stay well, I have to drink a gallon of it every day."
And while Ciara allowed herself to eat what she wanted while she was pregnant, she was determined to get back into shape as quickly as possible afterwards.
She said: "When I was pregnant with Future, one thing I learned quickly was, don't ever let a pregnant lady be hungry, because when I was, I was like the Tasmanian Devil! But as soon as the doctor said I could start training again, I was on the treadmill the very next day."