The Swedish royal family – apart from Princess Madeleine who lives with her husband Chris O'Neill in London – had dressed up to the nines for the first formal dinner of the year at the palace.

Representatives from parliament, the Swedish government, diplomats and the business industry were invited to the event, which was held in the lavish Charles XI's gallery, the main banqueting room of the palace where state visits are also held and Nobel laureates received by the royals.

But on Wednesday, all eyes where on Crown Princess Victoria and Princess Sofia, as the two pregnant princesses entered the hall alongside their husbands Prince Daniel and Prince Carl Philip.

Both sported elegant ball gowns as well as two almost full-size baby bellies. The Crown Princess is set to give birth to her second child next month, while Sofia's firstborn is expected to arrive in April.

Victoria has publicly denied rumours that she is expecting twins. She has also declined to reveal whether her eldest daughter, three-year-old Princess Estelle, will be getting a little brother or sister, instead joking with reporters last year: “What she really wants is a hamster!”

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Sofia and Carl Philip announced in October that they too were expecting their first child together, just months after the royal couple tied the knot at a big ceremony in Stockholm last summer.

They will both have plenty of cousins to play with. Carl Philip and Victoria's sister Madeleine gave birth to the currently youngest member of the Swedish royal family in June, Prince Nicolas. Her and O'Neill's other child, Princess Leonore, will turn two later in February.