The 42-year-old Australian was surrounded by children in Odense who wanted a glimpse of the Princess, and before cutting the ribbon she was handed the scissors by a young girl wearing a purple tiered dress straight out of Cinderella.
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Young ballet dancers were also on hand to celebrate the opening of the new park.
Mary, who last year was crowned the queen on style ahead of the Duchess of Cambridge, wore slim black pants and a white embroidered top, and kept warm with a simple black blazer. She paired her outfit with snakeskin heels and drop pearl earrings.
The mother-of-four stopped to take pictures with the waiting fans, and accepted several bunches of flowers, although her husband Prince Frederick, who is the next in line for the Danish throne, and her four children were notably absent.
Denmark's future king and queen had a blast at the amusement park with their children and nephews having headed out on a bright, sunny day from Grasten Palace in south Jutland, where they usually spend the summer.