Credit: AP Photo/Nick Ut

Things turned ugly when Paris Hilton and Cy Waits showed up to an L.A. courtroom to testify against an alleged home intruder on Wednesday.

After an overzealous fan broke through a group of photographers, he threw water in Waits' face and grabbed the nightclub owner by the neck; Hilton's security team quickly intervened and subdued the attacker.

"That other psycho intruder just punched Cy in the back of the head as we were walking into the court house," Hilton, 30, tweeted. "So scary!"

E! News confirms that the man is now in police custody. "After the attack, they realized he is the same intruder that showed up to her home on a bicycle a few months ago," Hilton's rep added. "They are both a bit shaken up but thankful security acted quickly."

The man, who later identified himself as Jim Rangford, later told E! News that he simply wanted an autograph from Hilton -- and to ask her father, Rick, for permission to pop the question.

"So creepy seeing that guy in court today," Hilton added. "It sent shivers down my spine."