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Sarah Ferguson just revealed the cutesy nickname she calls Princess Beatrice

The mother-of-two was celebrating Beatrice's 30th birthday

Ainhoa Barcelona

Sarah, Duchess of York is celebrating her daughter Princess Beatrice's birthday, and while the family will be marking the big 3-0 in private, Sarah couldn't resist sharing some gorgeous photos with royal fans. Prince Andrew's ex-wife also happened to reveal the very sweet nickname she calls her firstborn – Trixie Belle. Taking to Twitter and Instagram, she wrote: "Happy birthday my Trixie - Belle so proud of you xx."

Sarah, 58, posted three photos including two childhood snaps that also featured Beatrice's younger sister Princess Eugenie. The little girls looked adorable, wearing matching hand smocked dresses and flowery headbands as they posed in a garden. While Eugenie appeared to be in hysterics, her older sister smiled beautifully at the camera.

See Princess Beatrice's transformation through the years:

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The second shot was of Beatrice and Eugenie at a slightly older age, again wearing matching flowery hair ties, while the third photo showed Beatrice all grown up, looking sophisticated in a black top and monochrome striped skirt.

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The Duchess of York regularly shares photos of her daughters on Instagram, and on occasion her ex-husband Prince Andrew, who she is on great terms with. In June, she uploaded a photo of herself with Beatrice and Andrew at Royal Ascot and wrote: "Great day with my family." Another picture from the event showed her daughters taking part in the royal carriage procession. "So proud of my girls... Beatrice and @princesseugenie," she wrote.

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Eugenie and Beatrice looked adorable in their childhood photos

Sarah and Andrew were married for ten years until 1996. Despite splitting more than two decades ago, the exes have remained close friends. In an exclusive interview with HELLO! last year, the Duchess said: "A table can't stand on three legs, really, so you have the Duke and I, and the two girls. We're a family unit and we lead by example. We support each other emotionally and we support each other health wise. At least every two weeks we sit down and communicate, the four of us."

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Sarah shared the photos to celebrate Beatrice's 30th

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She added: "I think the one thing I've done incredibly well – although I say it myself – is that I'm a really good mum. And I think my girls show that."

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