Sienna Miller has said she was "spat at and abused" by paparazzi seeking a good photo, and that the hacking of her phone left her in a state of "complete anxiety and paranoia".
Giving evidence to the Leveson inquiry into media ethics on Thursday, the 28-year-old Hollywood actress recalled what her life was like before she obtained a court order banning photographers from pursuing her.
"I was 21. I would often find myself running down a dark street on my own with 10 big men chasing me," she said.
"If you take away the cameras what have you got? A pack of men chasing a woman. That's a very intimidating situation to be in."
Miller told the inquiry in central London that she was baffled at how so many stories about her private life kept appearing in the tabloid press. She began to suspect her close friends and family of selling stories to the media.
But it transpired that her phone had been hacked by the News of the World.
"I have a very tight group of friends. To this day no one has ever sold a story on me regardless of the fact they have been offered large amounts of money," she said.
"It was baffling how certain pieces of information kept coming out. I changed my mobile number, then I changed it again and again.
"I accused my friends and family of selling stories and they accused each other."
"It was my mother accusing people, people accusing my mother... everyone was very upset and confused and I felt very violated by this constant barrage of information being published."
After discovering her phone and the phones of her friends had been hacked, Miller reached a £100,000 settlement with the NotW.
Miller said she lived in "complete anxiety and paranoia" as she did not know where the stories were coming from.
"Every area of my life was under constant surveillance. I felt very violated and very paranoid," she told the inquiry.
"People found out before I'd even arrived before I was going. I didn't understand how they knew. I felt I was living in some sort of video game."
The inquiry has also heard from Max Mosely. The former president of the FIA won £60,000 in damages from the tabloid after it ran a story claiming he had taken part in a "Nazi orgy".
He told the inquiry that despite all other other things he had done in his life, it was the NotW story that he would be remembered for.
"Forever how long I live now that is the number one thing people think of when they hear my name," he said.
Harry Potter author JK Rowling, who has been upset at what she sees as undue intrusion by the media into the lives of her children, is due to be the final witness today.
The first witness to give evidence was protected from being identified by a High Court order and their session was not televised. It is alleged his phone was hacked while he was in a relationship with a celebrity.
Also giving evidence today is Mark Thompson, a lawyer who has acted for victims of hacking including Miller and her ex-husband Jude Law.
On Wednesday the parents of missing Madeline McCann hit out at the British media for the way it treated the family following the search for their four-year-old daughter.
Kate McCann told the inquiry she felt "totally violated" by the News of the World after it published her diary without her permission.