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Very hot mama.

On Thursday, Heidi Klum stepped out in a bikini for the first time since giving birth to her fourth child, daughter Lou, last year.

The mother of four, 36, is on a family getaway in Mexico. (To mark their fifth wedding anniversary, she and husband Seal are set to renew their vows this weekend.)

Getting her pre-baby body back wasn't simple.

"You don't walk out of the hospital and get right back into your 27s," Klum told February's InStyle.

So how did she shed 25 lbs. in just six weeks?

Not only did she cut out carbs, she also relied on light workouts using an exercise ball.

She also has credited her good genes.

During her pregnancy, "I never really had so many cravings or weight issues [during pregnancy]," she recently told

Being a mother to Leni, 6, Henry, 4, Johan, 3, and Lou, 7 months also keeps her active. "I think you should have a great time with it," she has said of motherhood. "It's such an amazing experience."