Dave Chappelle Performs, Smokes with Snoop Dogg at Napa Music Festival

Dave Chappelle was letting it rip this weekend -- smoking and singing songs next to Snoop Dogg up in Northern California ... and the guy's wife was in on the fun as well!

The comedian was on hand Friday night at the Blue Note Jazz Festival in Napa Valley, where he took the stage next to SD to not just tell jokes and talk ... but to actually flex his pipes a bit. Indeed, they were rapping and crooning together -- and it's pretty funny.

Of course, Dave was also kind of in scavenger mode -- smoking what appeared to be a blunt with Snoop -- and the Doggfather actually comments on it at the end of the clip.

Essentially, Snoop says Dave was transforming into himself right before his eyes the more weed he took in -- and he goes on to explain that's why he doesn't like toke up with that many people ... otherwise, there'd be a crap ton of Snoop Doggs running around. 😆

BTW, DC's wife, Elaine, was also there during the festivities ... and it looks like she was having a ball alongside her hubby. There's photos of the two of them hugging up on each other, but this shot here kinda captures the vibe of the night in full.