Could Paris Only Do Half The Time?

5/11/2007 12:59 PM PDT

Could Paris Only Do Half The Time?

TMZ has learned that despite published reports, the Los Angeles County Sheriff's Department will not know the length of Paris' time behind bars until the day the socialite reports to County Jail.

A report today in the Los Angeles Times indicates Ms. Hilton might spend just three weeks behind bars, representing just half of her original sentence of 45 days.

Sheriff's spokesperson Steve Whitmore tells TMZ, "At this point, we will not know exactly how much time she will do until the day she is booked."

As TMZ first reported, sources connected to the judge who sentenced her tell us that the heiress' only saving grace is a program called "Good Time, Work Time" designed to cut down sentences as a result of good behavior. The formula, considering Paris is allegedly a good girl, will calculate to 39 days ... unless there's some change at Hilton's check-in time.