The biggest perk of having a spin-off of a successful show is the potential to see those series crossover. The issue with The Big Bang Theory and Young Sheldon — the No. 1 comedy in overall viewers and No. 1 new comedy, respectivelyis that there's a 30-year time difference between the two shows.

That means it's a little hard to transport your favorite characters from Big Bang to a small town in Texas three decades earlier, but Chuck Lorre and his producing team are actively talking about having the adult versions of the Young Sheldon cast show up on Big Bang.

"We are all in love with young Billy Sparks, so if he walked into Pasadena it would be a thrill," Lorre told reporters during a Young Sheldon set visit as part of the Television Critics Association winter press tour. "That would be something."

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Billy Sparks (Wyatt McClure) was already mentioned on The Big Bang Theory in Season 3's "The Creepy Candy Coating Corollary," so it wouldn't be too weird to see his adult self eating dinner at the Pasadena Cheesecake Factory or another of the group's hangout spots. Lorre mentioned during the same visit that he envisions Matthew McConaughey as a potential casting choice for an adult Georgie (Montana Jordan).

There has also been serious talk about having adult Tam (Ryan Phuong) — young Sheldon's only friend — pop in to say hello to adult Sheldon (Jim Parsons) on the multi-cam comedy.

"We are very much talking about it," Lorre explained. "Again, it goes back to the organization and planning [of the episodes.]"

Which Young Sheldon character would you most like to see on The Big Bang Theory?

The Big Bang Theory airs Thursdays at 8/7c on CBS, followed by Young Sheldon.

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