Princess Beatrice, Sarah Ferguson and Princess Eugenie.Photo: David M Benett/Dave Benett/Getty Images

Princess Beatrice of York, Sarah Ferguson, Duchess of York and Princess Eugenie of York attend the launch of The Ned

Sarah Fergusonhas much to celebrate on the U.K.‘sMother’s Day.

The Duchess of York, 63, marked the annual holiday, which is known as “Mothering Sunday” and celebrated in the U.K. this year on March 19, with a tribute to her daughtersPrincess BeatriceandPrincess Eugenie, sharing a throwback to Instagram of the two of them as kids.

“I’m so proud of my girlsand the beautiful women and mothers they have grown up to be,” wrote Ferguson in the caption. “I feel extremely blessed to call them mine. My darlings, you are my sunshine always & forever. #happymothersday”

In a post on her own Instagram page, Eugenie shared a photograph of herself and her son, captioning it, “I love being your Mumma! Happy Mothers Day! Xx.”

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In another, which featured a photo of herself hugging her daughter, the proud mom said, “So happy for my girlie.”

Ferguson said that her grandchildren “look like my girls” as she appeared earlier this month at The 92nd Street Y in New York City.

“August is teaching me to play trains and diggers,” said Ferguson. “And Sisi is just mini Beatrice, and she gets little pink tutus, cause Beatrice likes to dress her up like Barbie.”

Sarah Ferguson with Princess Beatrice and Princess Eugenie.Chris Jackson/Getty

Sarah Ferguson

TheMost Intriguing Ladyauthor previously told PEOPLE that her grandchildren “think I’m very funny” and “just follow me around like Peter Pan,” adding: “I’m ‘Super Gran Pan!'”

“Everyone says, ‘Oh, has it changed your life?’ And I go, ‘No, because I live [in the mindset of] 3- to 6-year-olds.’ So I’ve now got another audience that likes me,” said Ferguson, a longtime children’s book author and host of YouTube’sStorytime with Fergie and Friends.

RELATED VIDEO: Sarah Ferguson on What She Told Daughters Beatrice and Eugenie Growing Up: ‘I’ve Already Made Those Mistakes’

Ferguson alsobecame mother to a few furry faceswhen she and ex-husbandPrince Andrewtook over care forQueen Elizabeth’s corgis, Sandy and Muick (pronounced “Mick”), after the beloved monarchdied at age 96in September.

source: people.com