Paris Hilton, the US socialite and former TV star of The Simple Life, is doing well after her first night in a Los Angeles jail, her lawyer has said.
Paris Hilton has an hour a day to shower or make phone calls
Richard A Hutton added she would now "reflect on her life, to see what she can do to make the world better".
Hours after appearing at the MTV Movie Awards on Sunday, Hilton, 26, started her sentence at the LA County Jail.
She will serve 23 days in solitary confinement for violating her probation for a drink-driving conviction.
The socialite has been separated from the main prison population in a special unit that contains 12 cells, each holding two people.
The 3.7m by 2.4m cell has two bunks, a table, a sink, a toilet and a small window.
The Paris Hilton waxwork will wear the prison suit until she is out of jail
Hilton will spend 23 hours in her cell and has one hour to shower, watch television or make phone calls.
Former inmate and LA resident Shamarra Thomas, who spent two days in the main prison for neglecting to pay parking tickets, said conditions for the rest of the women were unpleasant.
"You have people defecating on themselves, urinating on themselves, sleeping on the ground - it's horrible," she said.
Hilton's lawyer said his client was "really being punished because of her celebrity".
Steve Whitmore from the Los Angeles County Sheriff's Department, which runs the jail, said: "Her demeanour was helpful. She was focused, she was cooperative."
Hilton was accompanied by her mother as she arrived at the jail. She was then fingerprinted, photographed, medically screened and issued with the jail's regulation orange jumpsuit.
After checking in, Hilton was given her first meal which was cereal, bread and juice.
Mr Hutton said his client is taking responsibility for her actions, adding: "She knows it's wrong, but her attitude is 'I'm going to come in here, I'm going to do my time, I'm going to get it over with and I'm going to show the world who I really am'."
Meanwhile the waxwork museum Madame Tussaud's in London has taken the opportunity to mock the celebrity socialite.
The wax mannequin of the star has been temporarily dressed in a black and white striped prison suit.