In Deliverance, a scene depicts Billy Redden playing banjo opposite Ronny Cox, who joins him on guitar. Redden could not actually play the banjo and the director thought his hand movements looked unconvincing. A local musician, Mike Addis, was brought in to depict the movement of the boy's left hand. Addis hid behind Redden, with his left arm in Redden's shirt sleeve. Careful camera angles kept Addis out of frame and completed the illusion, though anyone familiar with bluegrass banjo playing can see that the left-hand movements do not match up with the music produced, and that the banjo being used (an open-back instrument) could never produce the music one hears (clearly from a resonator banjo).
Lots of visual jokes (for lack of a better word) make it interesting. If you're all political, might not want to watch it. Whole point is based on the meme "Donald Trump, don't trust China. China is asshole."