Characters on "The Big Bang Theory" talk about several fandoms, and guest stars take those pop culture references to another level. This includes James Earl Jones' appearance during Season 7, Episode 14 — "The Convention Conundrum," and Sarah Michelle Gellar's cameo during Season 12, Episode 24 — "The Stockholm Syndrome," helping to mark the final episode of "The Big Bang Theory." The show also capitalizes on the core characters' love for "Star Trek," including bringing on LeVar Burton. And there's a reason why his appearance during Season 8, Episode 10 — "The Champagne Reflection," is so important.

In the episode, Burton is a guest on what is supposed to be the finale of Sheldon's (Jim Parsons) "Fun with Flags" web series. He reminds Sheldon to delete his contact information, marking an end of an era on "The Big Bang Theory" while pointing out that Burton and Sheldon essentially became friends after Sheldon first reaches out to him on Twitter during Season 4, Episode 17, "The Toast Derivation." In that episode, Sheldon hopes to join his new group of friends for a spirited get-together. Burton enters the event late and immediately leaves after seeing Stuart Bloom (Kevin Sussman), Barry Kripke (John Ross Bowie), and Zack (Brian Thomas Smith) perform karaoke.

Burton's subsequent appearances prove that his statement may not be true, seeing that Sheldon does receive Burton's contact information. And it's a moment that Burton has talked about in real life.

How Burton brought his friendship with Sheldon into the real world

Upon Jim Parsons' 2011 Primetime Emmy win in the category of outstanding lead actor in a comedy series, LeVar Burton wrote on Twitter, "Hey @billprady Please tell the lovely Jim Parsons now that he's an Emmy winner I'd happily reconsider a party invitation from Sheldon!" Of course, this is a fun nod to Burton's first appearance on "The Big Bang Theory" during "The Toast Derivation.

He told startrek.com, "It was fantastical fun." That fun included an appearance during Season 6, Episode 7 — "The Habitation Configuration," also featuring a cameo from fellow "Star Trek: The Next Generation" star Wil Wheaton. Both appeared on Sheldon's "Fun with Flags" show. In the episode, Sheldon introduces Burton by naming some of his biggest roles, including Geordie La Forge, who he played on "Star Trek: The Next Generation," among other installments in the franchise. But Burton said that he was excited to play himself on the small screen, despite the crew turning down some wardrobe choices he was asked to bring from home. "That's what's so great about it. I just get to be me. I'm at that stage of my career where people are calling me to play myself," he said.