Donny Davis died from alcohol and fentanyl intoxication ... TMZ has learned.
The Clark County Coroner has revealed his cause of death ... after getting autopsy results back for the longtime Vegas impersonator.
As we reported ... Donny tragically died in February in Vegas, where he was found in his hotel room bed ... after partying at a nearby hotel-casino, just hours before.
The beloved impersonator was well-known in Hollywood. He performed with Britney Spears, Miley Cyrus, Mariah Carey and Chelsea Handler ... just to name a few.
He became a regular on "Chelsea Lately" -- sometimes filling in for her go-to little person sidekick, Chuy Bravo. And, he was pals with Britney Spears for years. He was even hired as a dancer for Brit's Vegas residency show when it kicked off, back in 2013.
Donny did lots of private gigs for big stars like Paris Hilton, Victoria Beckham and Charlize Theron. But, his face also became familiar on the big screen ... appearing in 2017's "It's Gawd!" after being in "Pain and Gain."
He was 43.