The NCIS star took to Twitter.com just after 1am to detail her brush with danger, less than three months after she survived a scary attack by another transient, who threatened to kill her near her Hollywood home.

"And again," she posted, referring to the November (15) incident with suspect David Merck.

She then went on to describe her latest worrying encounter, revealing she had been driving home from work when she stopped at a red light in northern L.A. and handed cash to a vagrant.

"There was a pretty off homeless guy asking for money from drivers," she wrote. "I keep ones in my glove box for this very reason."

The man took the dollar bill from Perrette, but then things turned ugly as he allegedly grabbed her wrist and forced his head through the lowered window, demanding to know the time.

"He was in my car and I was scared," the 46-year-old recalled. "I looked at my dashboard and first said, 'I rebuke you satan in the name of Jesus Christ' Then said to him 'It's 5:37."

Perrette claims the man held on to her wrist for a moment longer, before releasing her arm and walking away.

The actress insists she is "learning" to be more careful around the homeless, adding, "I need to know both sides, be smart and be safe and give. But all of them at once."

The incident left her shaken, but she insists she is fine.

"I'm totally ok," she wrote after the story hit headlines on Wednesday afternoon. "It was just incredibly weird. Really weird."

It is not known if Perrette reported the scare to police.

Her last alleged attacker, Merck, remains in jail on $60,000 (£41,316) bail and is due to stand trial on two felony charges of making a criminal threat and false imprisonment by violence.