Royal fans lose it over Kate and Mary reunion: 'Future Queens'

The Duchess of Cambridge has met with Denmark's Queen Margrethe, and our very own Aussie royal Crown Princess Mary in Copenhagen as part of a two-day royal visit.

On Twitter, Kate said the trip "was all about understanding the very earliest stages of a child's development here in Denmark", and would also focus on children's mental health and wellbeing.

Catherine, Duchess of Cambridge and Crown Princess Mary of Denmark
The Duchess of Cambridge and Crown Princess Mary together had royal fans abuzz. Photo: Getty

On the final day of the visit, Kate and Mary had a special private lunch.

The pair, who will one day be Queens of their countries, have become friends after they first met during Prince William and Kate's official visit to Denmark in 2011 after their royal wedding.

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Mary and her husband Prince Frederik, who is heir to the throne in Denmark, also visited William and Kate in 2016. The couples attended Royal Ascot together.

Kate Duchess of Cambridge and Crown Princess Mary of Denmark
The women first met during Prince William and Kate's official visit to Denmark in 2011. Photo: Getty

Royal fans loved seeing the Duchess and Princess Mary together, taking to Twitter to share their thoughts.

"Future Queens!" one person wrote.

"Love these two royals," another said.

While a third raved: "Doesn’t get more royal than this, seriously this pics of the Duchess of Cambridge with the Crown Princess made me so happy."

The Duchess took a woodland walk with children and had a go at chopping a log while visiting a forest kindergarten in suburban Copenhagen on Wednesday.

She also visited the downtown Copenhagen Danner Crisis Center, a shelter that helps women exposed to domestic violence.

Britain's Catherine, Duchess of Cambridge (C) and Crown Princess Mary of Denmark (R) arrive at the Danner Crisis Center and shelter in Copenhagen
Kate and Mary arrive at the Danner Crisis Center and shelter in Copenhagen, Denmark. Photo: Getty

Kate also slid down a slide at the Lego Foundation PlayLab as part of the trip with her Royal Foundation Centre for Early Childhood, the first time she has taken the work of her institution to the international stage.

Before her solo trip to Denmark, the duchess revealed she spent a recent school holiday playing with Danish-made Lego bricks with her three children - Prince George, Princess Charlotte and Prince Louis - who were jealous she got to visit the Lego Foundation.

"My children are very jealous they weren't coming to see the Lego Foundation. They were like, 'hang on, there's Lego and we're not coming?'," said Kate, who arrived in the Danish capital on Tuesday and visited the Infant Mental Health Program at the University of Copenhagen.

In 2011, Kate visited the UNICEF Supply Division Center in Copenhagen with her husband Prince William and the heir to the Danish throne, Crown Prince Frederik and his Australian-born wife Mary.

Additional reporting by AAP.

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