Marius Borg Høiby tells NRK that he had used alcohol and cocaine at the time.
"I have several mental health issues that I have had throughout my upbringing and into adulthood. I have struggled with addiction for a longer period, something I have received treatment for previously", he says in the statement.
Apologizes
Marius Borg Høiby explains that he will now resume treatment, take his problems seriously, and that addiction does not excuse what happened.
"For me, it is most important to apologize to my girlfriend. She did not deserve what happened, or the extreme pressure from both Norwegian and foreign media. Being followed by photographers and journalists in such a situation, I know has been tough", he says.
Now, the 27-year-old says he wants to take responsibility for his actions, and his lawyer Øyvind Bratlien tells Norwegian TV2 that Borg Høiby thus admits guilt and is prepared to take his punishment. "Bodily harm" is the least severe degree of assault and can result in up to one year's imprisonment.
The girlfriend's lawyer Mette Yvonne Larsen says that her client has been waiting for Marius Borg Høiby to speak out.
She has had a tough time, but it is clear that the fact that he is coming out with this makes it much better for her. She is believed, and it is often good for women to be believed in such an event, says the lawyer.
Arrested at Skaugum
It was on the night of Sunday, August 4, that a friend of the affected woman is said to have raised the alarm that the Crown Princess's son had assaulted his girlfriend and smashed her apartment in central Oslo. The police then arrested Marius Borg Høiby at the Crown Prince's estate Skaugum outside the Norwegian capital.
Marius Borg Høiby has no royal title and has chosen to live his life outside the spotlight. His father is Morten Borg, with whom Crown Princess Mette-Marit lived before she became involved with Crown Prince Haakon