(usmagazine.com) - Paris Hilton may have smiled her way through Sarah Silverman's raunchy monologue at the MTV Movie Awards where the show's host poked fun at Hilton's stint in jail, but she wasn't laughing backstage. Hilton, 26, who turned herself in to serve her sentence only hours after the ceremony ended, was overheard fuming, "She's a f--king bitch. I hate her." (usmagazine.com) - Paris Hilton may have smiled her way through Sarah Silverman's raunchy monologue at the MTV Movie Awards where the show's host poked fun at Hilton's stint in jail, but she wasn't laughing backstage. Hilton, 26, who turned herself in to serve her sentence only hours after the ceremony ended, was overheard fuming, "She's a f--king bitch. I hate her." But Hilton shed no tears as she checked into the Century Regional Detention Facility in Lynwood, California, at 11:15 p.m. on June 3 to begin her sentence. "She was quiet," a source tells Us Weekly. After a medical screening, Hilton - in an orange uniform - entered her 100-square-foot cell at 1:30 a.m. on June 4. , at 11:15 p.m. on June 3 to begin her sentence. "She was quiet," a source tells Us Weekly. After a medical screening, Hilton - in an orange uniform - entered her 100-square-foot cell at 1:30 a.m. on June 4. At 2 p.m. -- after lunch was placed through a slot in her door -- she called her father, Rick, who could hear "clanging in the background," a source tells Us. (She can use the phone for 15 minutes a day.) Although she is alone for now, sources tell Us she could still get a cellmate.