Ex-NBA Star Shawne Williams Pleads Guilty to Drug Possession -- The Weed Was Mine!

Ex-NBA player Shawne Williams has pled guilty to possession of a controlled substance following his December arrest ... when cops busted him for smoking a blunt inside his Porsche.

As TMZ previously reported ... Williams was popped in a parking lot in Tennessee after a cop said he smelled weed coming from inside Williams' Panamera. Williams reportedly confessed to the officer that he had weed and codeine (cough syrup) in his car.

Following the arrest, Williams was charged with possession of a controlled substance (for the weed) and possession with intent to sell (for the codeine).

Williams pled guilty to weed possession today and was sentenced to one day in jail and a $500 fine. He was given credit for time served and has already paid the fee.

The codeine charge was dropped after the passenger in Williams' car claimed it was his ... not Williams'.

The lesson: always have a friend around to share the blame.