Victoria and Daniel all smiles at Margrethe's birthday gala, but where is Madeleine? Arm in arm with her fiancé, and with her brother Prince Carl at her side, Crown Princess Victoria was wearing her usual radiant smile as the trio attended Queen Margrethe's birthday celebrations.

But there was no sign of the other Swedish sibling, Princess Madeleine, or her fiancé Jonas Bergstrom, who are said to be in the midst of a relationship crisis.

A question mark had been hanging over the couple's attendance after a spate of stories stating they are on the brink of splitting up and have been living separate lives since January.

There was no official word on why they weren't at the event – an evening at the theatre – though it is possible they could have been amongst the group of royals affected by the travel chaos caused by the volcanic ash cloud currently hovering over Europe.

Those who were unable to make it included Victoria and Madeleine's parents Queen Silvia and King Carl Gustaf, and Norway's King Harald and Queen Sonja.

Crown Princess Mette-Marit of Norway arrived without her husband, Crown Prince Haakon. His plane was grounded in London and he was expected to arrive by car, late on Thursday.

She was kept company as she arrived at the theatre in Copenhagen by Crown Princess Mary and her husband Frederik.

Some 1,200 guests were in attendance, and well-wishers gathered outside to catch a glimpse of the royal invitees, who also included Prince Joachim and Princess Marie – stunning in a silk scarlett gown.

But the biggest cheer of the night was reserved for Queen Margrethe, a vision in an elegant emerald green dress.

Celebrations were due to continue on Friday with a banquet lunch hosted by the city of Copenhagen and a dinner at Fredensborg Palace.

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