Hilton served a 23-day jail sentence in Los Angeles last June for violating probation in an alcohol-related reckless-driving case. She vowed to focus on philanthropy afterward.

Meanwhile, Spears, 26, continued to unravel in the public eye after a rough year in which she shaved her head, checked in and out of rehab and attacked a car with an umbrella.

She was taken to a Los Angeles hospital by paramedics earlier this month after police were called to her home because of a dispute involving her two sons. A court commissioner decided to keep in effect an order suspending Spears' right to visit Jayden James, 1, and Sean Preston, 2.