(Cover) - EN Showbiz - Beyonc Knowles reportedly worked out five days a week to lose her post-pregnancy pounds.

The 30-year-old singer gave birth to daughter Blue Ivy in January and has snapped back into shape very quickly.

And her trainer Marco Borges tells Us Weekly that the singer had every right to show off her curves in a swimsuit in St. Bart's last month.

He said that she worked hard for it and put in the dedication five days a week.

"We do cardio and plyometric moves likes lunges and jumps on and off a bench," the fitness expert told the publication.

The Single Ladies star was aided in her weight loss by breast feeding but she also avoided processed food and stuck to grilled meats and vegetables.

"You don't have to eat only celery sticks," Marco said. "Be sensible and exercise constantly."

Beyonc is currently rehearsing for her first post-baby show which will be on May 25 in Atlantic City. (C) Cover Media