'Jury Duty' Star Ronald Gladden in New Ryan Reynolds Mint Mobile Ad

Ryan Reynolds is back with another timely ad for his cell phone company -- this time, he's recruited a guy who's recently famous for getting duped ... only now, he's in on the joke.

Of course, we're talking about Ronald Gladden, who's the star and main subject on the hit Amazon Freevee show "Jury Duty" -- which is basically the modern-day 'Joe Schmo Show' ... where one person thinks they're part of something real, and everyone else is an actor.

Ron has become an internet sensation since the series premiered last month, and now his new gig is starring in Ryan's latest Mint Mobile commercial -- which is awesome.

Watch ... RR starts by plugging all of Mint's services and features -- like the fact it's still $15/month -- which then prompts him to ask Ron if he can believe it. The guy walks into frame and responds, "No, this doesn't seem real" ... referring to the big "Jury Duty" reveal.

The 2 guys banter back and forth for a bit, before Ron says he has trust issues since he's been "through some s***" -- again, he's talking about his 'Truman Show'-esque time on the show. Ryan comes over and hugs him, saying he can trust him ... 'cause he's an actor. 😅

It's pretty funny, and just a testament to Reynolds having his finger on the pulse of pop culture. You might recall his Peloton ad, which also came out on the heels of big news.

Anyway, more good news for Ron ... the guy's been signed to a talent agency in the wake of his 'Jury' fame. Artists First -- which also reps Awkwafina, Minka Kelly and others -- snatched him up, and is now looking to get him more work.