Meghan Markle at the U.S. Open to cheer on Serena Williams. (Photo: Bang ShowBiz)

Duchess Meghan Markle, who is married to Britain’s Prince Harry, flew to New York City unannounced over the weekend to watch Serena Williams play in the U.S. Open final. But that’s not all.

The former “Suits” actress also had a secret rendezvous and you won’t believe where.

She dropped in on a yoga studio Friday (Sept. 6) for a quick, unpublicized session, surprising other members in the class.

Her entire trip to New York City was unannounced so she could watch gal pal Serena play for the women’s title. Unfortunately, she lost.

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All told, about 60 people were in the studio when Meghan appeared. Most recognized her, but kept their distance. They offered mostly “sweet, knowing smiles,” an eyewitness told People.

“She has been going to Modo Yoga for many years and tries to do so whenever she is in New York. It was the perfect remedy for jet lag,” the attendee said.

She will launch her capsule collection for Smart Works at an event in London on Sept. 12.

Meghan has been a patron of Smart Works, a charity that helps unemployed women regain the confidence they need to succeed in interviews and get back to work.

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She began working with the group in January and announced the collaboration in July.

Markle, 38, who worked with friend and designer Misha Nonoo on the line.

She previously explained that her idea for the collection came when she realized the clothes the charity already had were not the “right stylistic choices,” or always available in the right sizes.

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“When you walk into a Smart Works space you’re met with racks of clothing and an array of bags and shoes. Sometimes, however, it can be a potpourri of mismatched sizes and colors, not always the right stylistic choices or range of sizes.”

“To help with this, I asked Marks & Spencer, John Lewis & Partners, Jigsaw and my friends, the designer Misha Nonoo, if they were willing to design a capsule collection of more classic options for a workwear wardrobe.

“Taking the idea further, many of the brands agreed to use the one-for-one model: for each item purchased by a customer, one is donated to the charity. Not only does this allow us to be part of each other’s story, it reminds us we are in it together,” she said.

The Duchess of Sussex gave birth to son Archie in May. Yoga is one way she’s been working to get back in shape.

Meghan is a yoga devotee. She often worked out while filming her television show in Toronto, according to published reports.

Mother Doria Ragland is a yoga instructor in Los Angeles.

“I started doing mommy-and-me yoga with her when I was seven. I was very resistant as a kid, but she said, ‘Flower, you will find your practice – just give it time.’ In college, I started doing it more regularly,” she said in a 2016 interview before her marriage.

“As I’m getting older, my approach to aging is quite different. I make sure that I take care of my skin and body, especially with the work hours I have. And I don’t just take care of myself for aesthetic reasons but because how I feel is dictated by what I’m eating, how much rest I’m getting and how much water I’m drinking. If I don’t have time for a long workout, I’ll grab my dog and go for a quick run. Being active is my own moving meditation.”

Meghan prefers an upbeat Vinyasa class set to hip-hop music to get her blood pumping,” according to one report.

Before she joined the royal family, she was a regular fixture at Y7 Yoga, a hip-hop yoga studio in Los Angeles and New York. The fast-paced classes are held in a heated candle-lit studio and set to a soundtrack that might make you think of your favorite club.

Check out a video of Meghan working out while she was still appearing as Rachel Zane in “Suits.”