Snoop Dogg is now a certified member of the country music bandwagon … the megastar rapper recently joined Zac Brown Band for a cornfed cannabis anthem, and we caught their first live performance!!!

TMZ obtained video of Zac Brown Band mixing it up at Desert 5 Spot in Hollywood on Monday as they gear up for their upcoming “Love & Fear” album … and Snoop made a guest appearance.

The 3X-Grammy winners played a few crowd favorites, including their mega-hit “Chicken Fried,” but had a surprise in store when they told everyone to back up a few feet in order to film the next song for a music video.

Right on cue, Snoop Dogg comes out and joins the band for their collab “Let It Run” … rapping while puffing on a joint!!!

The song connects Snoop and ZBB’s love for tokin’ bluegrass and there were plenty of party favors to share.

During the performance, a table was sectioned off with beer and a pile of joints, but Snoop had to play it low-key backstage due to all the fans wanting to meet him.