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If a mysterious "Middleton family source" is to be believed, the Duchess has done almost nothing to achieve her enviable post-baby body.

"A few weeks after George was born, you could hardly tell she had just given birth," the source told Us Weekly, adding that Middleton had "hardly done anything to lose the weight."

According to the insider, Kate hasn't even changed her eating habits. "Kate's still breastfeeding and the small weight she gained while pregnant has just melted off. She's not dieting," said the source, who also revealed that Kate is simply continuing with her yoga routine, just as she did during her pregnancy.

But whatever she's doing, it's working. Middleton was spotted earlier this week outside of a Waitrose supermarket in Anglesey, Wales, and she was looking as slim as ever in a pair of skinny jeans and a striped top.

We suppose some people just have good genes.