Princess Mette-Marit of Norway’s son Marius Borg Høiby was arrested after an alleged altercation in an apartment in Frogner, Oslo.

Crown Princess Mette-Marit of Norway with her son Marius who was arrested (Image: Getty)

Crown Princess Mette-Marit of Norway’s son was arrested on Sunday night following a serious incident in Oslo.

Marius Borg Høiby, 27, spent more than 30 hours in custody after an alleged altercation in an apartment in Frogner after a woman in her 20s called the police.

According to Se og Hør, Borg Høiby allegedly attacked the woman ‘psychologically and physically’ and was arrested.

The woman was taken to hospital where she was diagnosed with a concussion before being released in the early hours of Monday morning.

Reports suggest that Borg Høiby was put in solitary confinement and a blood test was taken to find out if he was under the influence of drugs.

Police told Se og Hør: “A person was arrested and charged with assault and later released from custody.”

The apartment where the incident took place appeared to have been destroyed, according to Norwegian publication Dagbladet.

Borg Høiby is the eldest child of Princess Mette-Marit, who was a single mother when she met Crown Prince Haakon through mutual friends in 1999.

The 27-year-old is now reportedly at the royal Skaugum estate with his 50-year-old mother.

Crown Princess Mette-Marit of Norway with her son Marius who decided to step away from royal life (Image: Getty)

Crown Princess Mette-Marit with her family has postponed a trip to France to be with her son Marius (Image: Getty)

Princess Mette-Marit was due to attend the men’s 1500-metre final at the Paris Olympics last night, but Crown Prince Haakon appeared in the stands alone.

Norwegian Palace confirmed to local media that the Crown Princess has decided to “temporarily postpone” her trip to France following the incident.

“The Crown Princess has temporarily postponed her departure and hopes to travel down later”, the Palace’s communications chief wrote in a text message to Se og Hør.

Øyvind Bratlien, who has expertise in high-profile criminal cases, has been hired by Borg Høiby as his defence lawyer.

Growing up, Borg Høiby made public appearances with his mother, stepfather and half sister Ingrid Alexandra, the future Queen of Norway, and half brother Prince Sverre Magnus on occasions such as national day.

However, when Borg Høiby turned 20 the royal court announced that he was stepping away from public life and his profile was removed from the Royal Family’s official website.