Conrad Hilton has been arrested for breaking into his ex-girlfriend's home.

The 21-year-old socialite was reportedly taken into police custody on Monday (22.06.15) for entering Hunter Salomon's Hollywood residence, despite the 21-year-old beauty having a restraining order against him.

According to TMZ, police - some in helicopters - ''swarmed'' the house and arrested Conrad, who is believed to still be in custody.

Hunter - whose father Rick Salomon infamously starred in a sex tape with Conrad's older sister Paris Hilton - previously filed documents against her former boyfriend in which she claims he said he will commit suicide, threatened violence and asked for her hand in marriage while visiting her at her mother's house.

A restraining order stated Conrad must stay 100 yards away from Hunter, her sister Tyson, her mother E. G. Daily and her father.

In the court papers Hunter says he ''asked if he could please just see me before he kills himself'', and claims Conrad told her to ''get a restraining order because he can't restrain himself.''

Conrad's latest arrest comes just a week after he was sentenced to a $5,000 fine, 750 hours of community service and to undergo treatment at a mental health and substance abuse centre following an incident on board a British Airway flight from London to Los Angeles last July.

The hotel heir had previously pleaded guilty to a misdemeanor count of simple assault following his 10-hour meltdown on the plane, during which he reportedly screamed threats at flight attendants.