The long-running geek sitcom The Big Bang Theory was known for its cameos. There was a standing rivalry between Dr. Sheldon Cooper and Star Trek actor Wil Wheaton. Bill Gates came to town in one episode. Heck, Mark Hamill officiated a wedding to thank a character for finding his dog. The most memorable episode for many Star Wars fans is the Season 7 episode "The Convention Conundrum." When the "adorkable" main characters fail to get passes to San Diego Comic-Con, they're devastated to think of the panels, celebrity appearances, and camaraderie they'll miss. They start brainstorming people they could invite to their own con.
Amid all their brainstorming, they think of George Lucas, Billy Dee Williams, Mark Hamill, Harrison Ford, Carrie Fisher, etc., but leave James Earl Jones off the list. A few minutes of screen time later, Sheldon announces that he's got a chance with a major celebrity. While his friends think he'll have to use duct tape and chloroform and foresee that "Darth Vader will pour soy sauce on your head," he heads to James Earl Jones' favorite sushi restaurant.
Thus begins one of the funniest subplots of the show. Rather than rebuff him, James Earl Jones professes his love of Star Wars and talks Sheldon into spending some time with him. They sing karaoke, go to a sauna, even ride a Ferris wheel. But things get really fun when James brings his new friend to a house for a harmless prank.
Executive Producer Steven Molaro told via IGN that "we learned that Carrie and James Earl Jones had never met in real life" because Jones recorded Darth Vader's lines in a sound booth. James described the ding-dong-ditch as a "very little scene that was a way to bounce off each other."
The "little scene," which shows a frazzled and bathrobed Carrie Fisher coming to the door with a baseball bat to protest the prank, was conceived of by Jones himself. "It's not FUNNY anymore, James!" Fisher bawls at the chortling Sith Lord. Behind the scenes, she responded much more positively, calling him "Dad" when they met.
The scene is the perfect Dad joke: mortifying for the recipient and highly enjoyable for the perpetrator. Jones said, "It was sweet. It was finally good to meet her." We can imagine that they're having another family reunion now that James Earl Jones has joined Carrie Fisher in the Force.