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The apple of her parents' eye, Estelle has displayed her fun and playful personality during many official engagements with Princess Victoria and Prince Daniel.
The young royal was as good as gold during her aunt Princess Madeleine's wedding and took pride of place waving her Swedish flag for King Carl XVI Gustaf's 40th Jubilee celebrations.
In honour of Estelle's special day, HELLO! Online brings you a gallery of her sweetest moments...