'Young Sheldon': How Sheldon and Amy Came Back in the Series Finale

Young Sheldon

It's been known for awhile that Jim Parsons and Mayim Bialik would reprise their characters from "The Big Bang Theory" for the series finale of CBS spin-off "Young Sheldon," but what hasn't been totally clear is how they'd fit into the story. Well, now we know.

A few sneak peek images released ahead of the episode hinted at what was to come, with the older version of Sheldon (Parsons) sitting at his laptop while Amy (Bialik) looked over his shoulder. That, plus the series finale title of "Memoir," seemed to indicate that their return would be tied to Sheldon writing a book about his life.

And indeed, that ended up being the case. Though Bialik and Parsons didn't appear in the first 30 minutes of the two-episode finale, they popped up less than two minutes into the second half, being the Shamy that fans remember, and revealing that Sheldon is deep into writing his memoir.

As Sheldon recalled going to church with his mother simply to make her happy, his voiceover noted that he was "always doing things to make other people happy." At that, we flash forward to present day, with Amy scolding Sheldon for making that claim.

The two had a brief verbal sparring match, with Amy reminding him exactly how much he's historically hated doing things for others, and ending with Sheldon lovingly noting that "the passion is still there" even after years of being married.

According to "Young Sheldon" boss Steve Holland, tying the couple's return to Sheldon's memoir wasn't always the plan, as fans have long theorized, it just ended up being the most practical way to do so.

"They don't take place in the same time frame, they can't interact with their younger selves unless you do something crazy out of tone of the show, where he invents time travel or something," Holland explained. "So that seemed like the most sort of natural way, that you finally saw. This is what we've been hearing this whole time. This was sort of what we've been watching this whole time, was adult Sheldon writing the memoirs of his childhood."

Throughout the final episode, fans were treated to a few more flash forwards, playing out as Sheldon and Amy argue over him going to his son Leonard's hockey game. True to character, Sheldon didn't want to go — because sports. But, as he recalled how his parents loved him and supported his interests, Amy effectively hit him over the head with the parallel.

"I kind of liked that, you know, Sheldon recounting the story of his parents has missed the most obvious point entirely, which is that his parents, who didn't understand him, were always there for him," Holland said. "And it takes Amy to show Sheldon the way."

One of those flash forwards also confirmed that Sheldon and Amy have a second child — a daughter, who wants to take acting classes. Naturally, Sheldon blames Penny (Kaley Cuoco's character from "The Big Bang Theory") for that, having babysat for them before.

In the end, the final appearance of grown-up Sheldon came as he walked through his childhood home, remembering exactly how it was when he left for Cal-Tech. And so ends "Young Sheldon."

"Young Sheldon" is available to stream on Netflix and Paramount+. The series finale will be available on-demand for Paramount+ Essential subscribers beginning Friday.