There was doubt as to whether she would show, after pictures were published of her husband with another woman in Thailand.
But Princess Caroline of Monaco finally arrived in court on Wednesday to testify on Ernst August of Hanover's behalf in his assault trial.
The Monegasque royal looked strained as she walked past photographers and entered the building in central Germany.
Ernst August, who was absent from proceedings, admits slapping a German neighbour at his holiday home on the coast at Lamu, Kenya, during an incident which took place ten years ago.
But he denies he had a metal knuckleduster on his fingers, as prosecutors are claiming.
Caroline told the court in fluent German that her husband had hit the neighbour – who owned a noisy dance club – twice "one for the music and one for the lights" but had applied "no other force".