Nicole Richie was supposed to serve four whole days in jail for her DUI charge ... but she only served 82 minutes!
Richie was accompanied by her lawyer and baby daddy Joel Madden on Thursday, when she entered the jail in Lynwood, California.
Thw whole thing tok 82 minutes ... she got in, a mug shot was taken, she got booked & processed into the system then released.
But, it seems this wasn't special treatment, a sheriff's statement said: "Richie was treated in the same manner as other inmates with a similar sentence."

This is explained by the current sheriff's policy for non-violent female offenders, if they are sentenced to 30 days or less, they are booked and released within 12 hours.
Not only that, but there was also overcrownding at the facility ... there was no room for the 5-month pregnant celebrity.
But that's not the end of it for Nicole, as part of her sentence, she also agreed to serve a three-year probation term & enroll in an alcohol education program and was fined $2,048.