-- Hours after strolling the red carpet in a strapless black dress, Paris Hilton traded her designer duds for a jail-issued jumpsuit.

The 26-year-old heiress checked into the Century Regional Detention Facility in Lynwood just after 11:30 p.m. Sunday. She's expected to serve three weeks for violating her probation in an alcohol-related reckless driving case.

Hilton surrendered to sheriff's deputies after making a surprise visit to the MTV Movie Awards in the afternoon.

"I am trying to be strong right now," she told reporters on the red carpet. "I'm ready to face my sentence. Even though this is a really hard time, I have my family, my friends and my fans to support me, and that's really helpful." (Watch Hilton make her comments Video)

Sheriff's spokesman Steve Whitmore said Hilton was easy to work with.

"Her demeanor was helpful. She was focused, she was cooperative," he said. (Watch how playtime for Paris is over Video)

Hilton turned herself in at the Men's Central Jail in downtown Los Angeles just after 10:30 p.m., then was escorted to the all women's facility in Lynwood, where she was booked, fingerprinted and issued a jail uniform, Whitmore said.

She also was given her first meal: cereal, bread and juice.

So far, Hilton does not have a cellmate, Whitmore said.

The "Simple Life" star will be housed in the "special needs" unit of the 13-year-old jail, separate from most of its 2,200 inmates. The unit contains 12 two-person cells reserved for police officers, public officials, celebrities and other high-profile inmates.

Like other inmates in that unit, Hilton will take her meals in her cell and will be allowed outside the 12-foot-by-8-foot space for at least an hour each day to shower, watch TV in the day room, participate in outdoor recreation or talk on the telephone. No cell phones or BlackBerrys are permitted in the facility, even for visitors.

The jail, a two-story concrete building next to train tracks and beneath a bustling freeway, has been an all-female facility since March 2006. It's located in an industrial area about five miles southeast of downtown Los Angeles.

"I did have a choice to go to a pay jail," Hilton said Sunday, without giving details. "But I declined because I feel like the media portrays me in a way that I'm not and that's why I wanted to go to county, to show that I can do it and I'm going to be treated like everyone else. I'm going to do the time, I'm going to do it the right way."

When she was sentenced May 4, Superior Court Judge Michael T. Sauer ruled that she would not be allowed any work release, furloughs or use of an alternative jail or electronic monitoring in lieu of jail.

Sometimes stars are allowed to do their time in a jail of their choosing. In such cases they pay a daily room-and-board fee to the smaller jails, which afford them more privacy and comfort.

Cop-slapping actress Zsa Zsa Gabor, for example, served three days behind bars in 1990 at the El Segundo jail near the Los Angeles International Airport. She paid $85 a day.

On Saturday, about 15 photographers, reporters and television crews staked out the entrances to the jail waiting for the celebutante's arrival. Authorities had also cordoned off a grassy area outside the facility for the media. She had until Tuesday to report.

On Sunday, about a dozen photographers and television crews were at the Lynwood facility when she arrived in an unmarked SUV. Video captured by celebrity news site TMZ.com showed Hilton inside the vehicle with her mother, Kathy.

Hilton's publicist, Elliot Mintz, said he spoke with Kathy Hilton after she returned from the jail.

"She told me it was very emotional," Mintz said. "She also said that she feels this will be a time when Paris will be able to think and reflect and to spend time alone to learn from the experience because in Paris' life she's never alone -- there's always a constant chatter around her."

Officers arrested Hilton in Hollywood on September 7. In January, she pleaded no contest to the reckless-driving charge and was sentenced to 36 months' probation, alcohol education and $1,500 in fines.

She was pulled over by California Highway Patrol on January 15. Officers informed Hilton she was driving on a suspended license and she signed a document acknowledging she was not to drive. She then was pulled over by sheriff's deputies on February 27, at which time she was charged with violating her probation.