Scott Weiland Found Dead on Tour Bus

6:20 AM PST -- An official statement on Weiland's Instagram page says the singer passed away in his sleep.

Rock star Scott Weiland was found dead on his tour bus in Minnesota ... TMZ has learned.

Weiland was on tour with his band Scott Weiland & The Wildabouts ... they were supposed to play the Medina Ballroom tonight, but the show was cancelled. A source connected to the band tells us Scott was found Thursday night on the bus around 9 PM.

Police surrounded the bus, which was parked outside a motel in the town of Bloomington, MN. The Hennepin County Coroner now has Weiland's body.

The former lead singer for Stone Temple Pilots and Velvet Revolver famously battled substance abuse for years. We're told he died in his sleep but it's unclear what caused his death.

Scott was 48.