'Entourage' Creator Doug Ellin -- Rescued From the Middle of Nowhere ... By Big-Time Producer

Where the hell's Turtle when ya need him? "Entourage" creator Doug Ellin got stranded in the desert and had to use social media to find a knight in shining armor ... in the form of "Rambo" movie producer.

Ellin's Mercedes suffered a flat tire in the middle of the desert Sunday afternoon between Palm Springs and Los Angeles. With no spare tire, and AAA only willing to tow him seven miles, Ellin was SOL.

So he posted a photo of the bum wheel on Instagram and in a twist of fate, Randall Emmett -- who has produced movies like "Lone Survivor," "2 Guns," and the last "Rambo" flick -- happened to see the post and happened to also be driving back from Palm Springs ... so he decided to scoop up Ellin and his fiancée in his sick Rolls-Royce.

Emmett tells TMZ, "We were all in shock that the timing worked out and we were mostly blown away by the power of social media. We couldn’t believe it."

FYI -- Ellin's car is still in the desert, waiting to be towed. We smell a road trip for Turtle.