The use of the word “storyline” is also curious. It seems more likely a Big Bang Theory character will join adult Sheldon for some sort of reference or joke from the original show. Hopefully, as Molaro indicated, it will serve as a fun moment for viewers of both The Big Bang Theory and Young Sheldon. Audiences will find out for sure when Young Sheldon season 4 begins on Thursday.
Speaking with TVLine, Young Sheldon co-creator Steve Molaro revealed fans of the original show are in for a treat in the season 4 premiere, which airs this week. Molaro stated it has to do with Parsons’ role specifically, saying, “Adult Sheldon is not alone in his narration at the end of the episode. It’s a fun, unexpected continuation of the Big Bang Theory storyline.”
It’s hard to say for sure who will join Parsons in the premiere episode. The Big Bang Theory didn’t utilize narration, so there are no clues to be garnered from that. However, it’s worth noting it would be much easier for a core cast member from the original show to pop by via voiceover than in person.