Meghan Markle Reacts to Her High School Sharing a Rare Throwback Pic on Instagram: 'Biggest Smile'

Meghan Markle's high school is celebrating her latest achievements.

On March 18, Immaculate Heart college preparatory school shared a surprise post featuring a famous alumna: the future Duchess of Sussex. The photo showed a young Meghan, now 43, smiling while standing beside a photo of Mary, the mother of Jesus.

The all-girls Catholic school in Los Angeles captioned the image, "Congratulations to IH alumna Meghan Markle ('99) on the renewal of her Netflix series and launch of her new podcast!"

"We’re delighted to share a special throwback photo from her time at Immaculate Heart, honoring our cherished tradition of Mary’s Day, a reflection of our legacy of sisterhood, support and Panda spirit," they added. "As we begin preparations for this year’s Mary’s Day celebration, we proudly carry forward the traditions that make our school community so special!"

Shortly after, Meghan shared the image on her personal Instagram page, which she launched at the start of the year.

"When your dear friend from middle school/high school sends you something from your Alma mater and it brings the biggest smile to your face. Go Pandas," the Duchess of Sussex wrote, adding, "Thanks Sush xo."

Meghan's Immaculate Heart schoolmate told PEOPLE in 2016, “Meghan was really charismatic and was a very hard worker and very focused, and you could tell she was going to do something special with her life."

Meghan returned to her school for an episode of her podcast Archetypes, which aired in 2022.

"Oh, my gosh. How funny. My locker was right over here," she said in the episode. "I was somewhere smack in the middle. I don't remember because these are your lockers when you're in high school and the middle school lockers were up there."

Prince Harry's wife said, "You've heard me talk about Immaculate Heart on the series before and the influence it's had on my life. And look I was there from ages, about 12 to 17 which are really formative years in your life – they certainly were for me. And let me just say, being back there, the energy, it was, it was palpable. I was happy to be back there, and it was also really fun — especially when I made a surprise visit and I popped into some of the young ladies in volleyball practice."

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The Duchess of Sussex also made a surprise commencement speech to the graduating class of her alma mater in 2020, where she addressed the "absolutely devastating" killing of George Floyd and the social unrest in the wake of his death.

"She had planned to share a heartfelt congratulations to the class of 2020, who have worked so hard over the past four years, by sharing some words of support, encouragement and offering some memories of her own time at the school," a spokesperson for Meghan said at the time. "However, in the video message she shared, she felt compelled to directly address and speak to these young women about what’s happening in this country right now around the killing of George Floyd — as well as what’s been happening over many, many years and many, many generations to countless other Black Americans."

After marrying Prince Harry in 2018 and stepping back from their roles as working members of the royal family, the couple relocated to Meghan's home state of California in 2020, where they continue to live with their 5-year-old son, Prince Archie, and 3-year-old daughter, Princess Lilibet.

She recently opened up to PEOPLE about how the Montecito community, who have gotten to know her from school drop-offs and playdates with Archie and Lili, have become essential.

“We hosted a little camp because winter break was long!” she said. “We had several days with different families at our home, and we were able to get to know the parents better, and all the kids could play.” Meghan and Harry set up obstacle courses and face painting. “It’s a dream,” she added. “But I also know that being part of a community means you put effort into it.”