Sienna Miller felt "violated" by having her phone hacked and being put under a "web of surveillance", the actress and model told the Leveson Inquiry.
"Every area of my life was under constant surveillance," she said.
Miller outlined the "damage" it had caused her relationships with friends and family, as private details of her life known only by a few people close to her were reported by the press.
"Horribly, I accused friends and family of selling stories," she said.
It was "baffling" how the information got out, though it was later revealed her phone messages and emails had been hacked, as well as those of the people close to her.
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"I feel terrible that I would even consider accusing people of betraying me like that, especially people who would rather die than betray me."
The intrusions left her "scared" and "intensely paranoid".
She also told Leveson how papparazi "abused" and "spat at" her.
Their pusuit of her on motorbikes was a "daily occurance" and "really terrifying".
She spoke of being a 21-year-old woman being chased down dark streets by a "pack of men" with cameras, which she found "very intimidating".
In May 2011, Miller secured £100,000 in damages from News International after it admitted people working for its now defunct Sunday tabloid News of the World hacked into her phone.
"I was very nervous of taking on an empire that is richer and more powerful than I will ever be," Miller said.
After being shown a "stack of evidence" by police, including a private investigators notes that detailed her phone numbers, pins and email address password, Miller felt she "couldn't not do something about it".
She described the detailed notes on her and those around her, by private investigator Glenn Mulcaire, appeared like her life was a "project".
