Meghan Markle is in no hurry to get her pre-baby body back.

ET recently spoke with royal expert Katie Nicholl, who tells ET that the 37-year-old Duchess of Sussex has been taking a relaxed approach to fitness since giving birth in May to her first child -- son Archie -- with her husband, Prince Harry.

"Before she fell pregnant, you know, Meghan was very fit," Nicholl notes. "She was very into her fitness regime. She used to run around the park in Kensington, but she has been taking it easy. And I hear that yoga is very much on her post-birth fitness regime -- nothing too strenuous."

"As I say, the whole approach has been holistic, it has been gentle," Nicholl continues. "It's been a natural embracing of motherhood, and with that has come a pretty gentle routine. ... Meghan hasn't been hitting the gym. She hasn't been in any hurry to get back in shape. It's only four weeks really since the birth and she's been taking that exercise regime very gently, indeed."

According to Nicholl, Meghan has been practicing yoga with her mother, Doria Ragland, who's a yoga teacher.

"Apparently Doria took up postpartum yoga and baby yoga, and that's all Meghan has been doing," Nicholl says. "And lots of proud walks around Windsor Great Park, so, gentle exercise, but no hard training, no weights. She's apparently not in any hurry to ping back into shape. She's enjoying this time. She's being gentle to herself."

Meghan is no stranger to taking a holistic, natural approach. In April, ahead of Archie's birth, Meghan and 34-year-old Harry were spotted making a visit to the natural remedy store ilapothecary, described on their website as an "urban hideaway" that offers "healing therapies, unique remedies and workshops to help you create solutions to issues you may be facing, relieve bodily symptoms and escape from stresses of urban living."

Last March, Nicholl told ET that Meghan's healthy lifestyle has been a good influence on Harry.

"There's a park outside Kensington Palace and Meghan has been seen running a circuit there. She's often in and out of the gym," Nicholl said at the time. "Meghan is a complete fitness fanatic. She loves to run laps around Kensington gardens, which is just outside Kensington Palace. I'm told that she's a fan of a private members club that does intensive fitness training classes, it's called the Skinny B**ch Collective. She was introduced to it by her friend, Millie Mackintosh. She loves her yoga, in fact, she starts most mornings with a yoga ritual and that's rubbed off on Prince Harry."

"One of the things I was told by a friend of his .... is that he's also getting into yoga," she continued. "He likes to start his day with a green juice now, just like Meghan, and his friends all find this very amusing that he's turned into a bit of a fitness fanatic himself. You'll often see him visiting the gym and he's given up his beloved Marlboro Lights, or at least he's smoking less and he's drinking less. So, Meghan and her green L.A. lifestyle I think have really rubbed off on the prince, and for the better."

For more on how being new parents has also brought Meghan and Harry closer to Kate Middleton and Prince William, watch the video below:

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