But despite sharing a post-baby bounce-back with her sister, Kate Middleton (AKA the Duchess of Cambridge), Middleton's impressive physique is due more to hard work than lucky genetics.
In a series of interviews, Middleton opened up about her rigorous fitness and health routine, which she has maintained throughout and after her pregnancy.
From Barrecore to a newfound love of swimming, here's how the Lady-to-be got those abs.
When it comes to fitness, Middleton didn't slow down too much during her pregnancy. Penning a fitness journal for Waitrose, Middleton noted that she was "able to carry as normal and continue my sports" as she had no morning sickness.
She revealed: "I worked out for 45 minutes, 3-4 times a week, depending on my energy levels but ensured that the routines I did were lighter than usual."
Counting running, jogging, swimming and tennis as exercise go-tos to keep her fit, Middleton noted that the fresh air was "better than ever for clearing the head and keeping the body active."
In addition to her out-of-doors activity, the British socialite regularly attended classes for "Barrecore, strength and conditioning, Pilates or yoga."
Although the mother-of-one hasn't spoken about the specific diet she maintained during her pregnancy, she has touched on her approach to clean eating in the past.
"I try to eat whole-grain, energy-fuelled carbohydrates and three meals a day," she previously told a publication.
"I always have breakfast. I can't start the day properly without it," she said. "My usual breakfast is either plain yogurt with chopped fruit and toasted seeds, oats, and nuts or toasted rye bread with eggs or avocado."
When training for an event or marathon, Middleton amps things up. "I also increase my portion sizes based on my training level, with lots of brown rice, lentils, quinoa, and sweet potato, and for breakfast, porridge and rye toast. A week or so before an event, I cut out alcohol, refined sugar, and processed foods."