Park Yoo-hwan is set to go to court over the break-up of his relationship, which the plaintiff insists was a de-facto marriage.

The plaintiff claims she had been in a common-law marriage with the 25-year-old, and accuses Park of unfairly retreating from the relationship.

Park Yoo-hwan (left) and Park Yoo-chun

The star’s agency C-Jes Entertainment said the case was a civil suit, and that the agency will release an official statement once a verdict is made.

It declined to comment on the exact relationship Park had with the plaintiff, citing Park’s rights to privacy.

Park Yoo-hwan’s brother JYJ’s Park Yoo-chun has also had legal trouble recently, albeit of a more serious nature.

He was embroiled in a criminal suit mid-July with four women who claimed they were sexually assaulted by the hallyu star. Their accusations were dismissed for lack of evidence that the sexual acts were forced.

By Lim Jeong-yeo (kaylalim@heraldcorp.com)