While on set, Guillermo also met up with a few of the movie's biggest stars to get some acting tips -- starting with Chris Pratt, who told the talk show sidekick that acting really comes down to just a few simple expressions.
"There's three looks," explained Pratt, who stars as "Star-Lord" Peter Quill. "The first one: Happy; The next one: Sad; and then the third one: Scared. That's all you need."
As he listed off the looks, Guillermo tried his best to pull them off, with varying degrees of success, and asked about another important expression: "What about sexy?"
Later, Guillermo ran into Kurt Russell, who plays Quill's father, Ego, and the veteran action star -- decked out in his full, awesome GotG2 costume -- had one simple piece of advice: "Just remember this one thing -- whatever you do, don't f**k up."
The hilarious set tour also gave a sneak peek at Guillermo's cameo in the adventure saga in which he plays a police officer -- and it's a real challenge for everyone involved. Check out the clip to see how his first real acting gig turned out.