The star was among the musical guests invited to hit the stage at the Musikhuset Aarhus venue, where Queen Margrethe II and Prince Consort Henrik were treated to a special show after taking part in a parade through the city of Aarhus.

Danish actor Nikolaj Lie Kaas hosted the bash, while local artists Rasmus Seeback and Anne Linnet, comedy group Orkenens Sonner and royal ballet dancers Ida Praetorius and Sebastian Haynes also performed.

After the show, Groban took to his account to tell followers about his royal performance writing, "Denmark, it was a pleasure to be back in your beautiful country to sing for Queen Margarethe's 75'th birthday! To many more".

The Queen actually turns 75 on 16 April (15).