Kate Middleton has "hardly done anything" to shed her baby weight, a family source tells Us Weekly. Credit: Mark Cuthbert/UK Press via Getty Images

Kate Middleton is the ultimate super-mom. On Monday, Aug. 26, just five weeks after giving birth to Prince George, the Duchess of Cambridge went for a grocery run with an enviably thin frame. Still, a Middleton family source insists to Us Weekly that the new mom has "hardly done anything to lose the weight . . . she looks incredible. "A few weeks after George was born, you could hardly tell she had just given birth," the source marveled of Prince William's wife.

And indeed, 31-year-old Middleton looked radiant as she ran errands on Monday, Aug. 26, in Sebago flats, snug black skinny jeans and a black-and-white striped shirt. The royal even pushed her own shopping cart through the parking lot of her local Waitrose supermarket.

"Kate's still breastfeeding and the small weight she gained while pregnant has just melted off," the source continued. "She's not dieting. After giving birth, she did continue with her yoga."

During her pregnancy, Middleton frequently took brisk walks with the couple's dog Lupo and had prenatal yoga sessions with a private instructor.

Middleton and William, 31, have been taking things easy since the fanfare of George's arrival, spending time together as family in Anglesey while they await the renovation of their home in Apartment 1A at Kensington Palace.

And, according to 31-year-old William, the couple have been getting to know their little bundle of joy a little better in the meantime.

"He's a little bit of a rascal, put it that way," the proud father told CNN in a TV interview last week. "So he either reminds me of my brother or me when I was younger. I'm not sure. But he's doing very well at the moment."