NBA legend Bill Walton -- arguably the biggest Grateful Dead fan on the planet -- received a huge tribute at the Dead & Company Sphere show Thursday night ... three days after he tragically passed away.
The band -- which consists of John Mayer and Bob Weir, plus other former Grateful Dead members -- projected images of Walton behind them throughout their hourslong concert at the must-see attraction in Las Vegas.
Some of the pics displayed on the building's massive screens included Walton with Weir and Mickey Hart.