Alec Guinness Once Played a Hilarious Joke on a 'Star Wars' Extra ??

The Oscar-winning actor "really helped me get this guy," Mark Hamill told Johnny Carson.

Alec Guinness was the rock many of the Star Wars cast leaned on during the long shoot in 1976. 

Always the consummate professional, Guinness never complained, but did admit he was confused by the movie at times during production, castmembers have said in previous interviews. 

And it seems the Oscar-winning actor had a great sense of humor, too. 

Mark Hamill once told a story to Johnny Carson in an interview unearthed by Heat Vision about Guinness playing a joke on an extra named Jack, who was always busting other people's chops. Jack portrayed one of the Jawas and was an insult comedian by trade. 

"He would always insult you. You couldn't even get a joke in because he was just too funny," Hamill told Carson, adding that Guinness "really helped me get this guy." 

Hamill explained that Jack told him that he was in awe of working with Guinness, whom he had profound respect for.

Jack even claimed that they he and Guinness had a good rapport and Hamill believed him, until Jack revealed it to all be a joke when Jack said he and Guinness were so close they were on speaking terms. (As Jack told it, Guinness yelled at him to "get out of the way" when they were on a plane ... not exactly a close relationship.)

Hamill told Guinness that piece of information and the legendary actor took it from there. 

"Two weeks later, we're in the desert again," Hamill began. "It's complete open wilderness. You could walk with your eyes closed and never fall down. And Jack is sitting on his rock, reading a book, and Guinness started very slowly walking towards Jack. Guinness had the hood on ... he then pulled the hood back and said, 'Get out of my way! Get out!'" 

The moment so stunned Jack, he was shaking, Hamill recalled. 

"Jack said to me, I have to hand it to you, when you play a practical joke, you get the best talented people in England," Hamill said.

Hamill plays Luke Skywalker once again in The Last Jedi due out Dec. 15.

Watch Hamill tell the full story, with the voices, below: