Ended with a big bang: ‘Young Sheldon’ boss on series finale — and Jim Parsons and Mayim Bialik’s return

It all ended with a big bang.

“The Big Bang Theory’s” spinoff prequel series, “Young Sheldon,” has ended on CBS after seven seasons.

Spoilers ahead for the “Young Sheldon” series finale. 

In Wednesday night’s series finale, Sheldon (Iain Armitage) agreed to get baptized to please his mother, Mary (Zoe Perry), despite his atheism. He also finally went to Caltech, wrapping up the childhood chapter of his life.

Meanwhile, the show also had a flash-forward to Sheldon’s future, as original “The Big Bang Theory” stars Jim Parsons and Mayim Bialik reprised their roles as Sheldon and Amy.

“That just felt really exciting as a way to bring this thing to a close,” executive producer Steve Holland told The Post.

“And also just on a personal level, to get to have Jim and Mayim – because having done ‘The Big Bang Theory’ for many years; I spent a lot of my life with these two people – and they’re lovely. It was really fun to watch them step back into these characters as older versions.”

As the episode unfolds, scenes cut between young Sheldon and the older version of Sheldon, who is working on a memoir about his past. It’s also revealed that in the future, Sheldon and Amy have a son and daughter.

“It was exciting to have them back, but we wanted to make sure that they didn’t overwhelm the finale,” said Holland.

“At the end of the day, we really wanted to make sure this was a ‘Young Sheldon’ finale… This was a fun bow to tie around it. I feel pretty happy with the balance that we struck, where they’re not just a cameo at the end, which I think many people will expect. So hopefully, cutting to them right off the bat – people won’t be expecting that. But we wanted to make sure that we gave the Cooper family their due screen time in this last episode.”

Sheldon and Amy’s kids are discussed onscreen, but not shown.

“We wanted to keep this about Sheldon and not have to introduce the kids,” he said.

“This is an older Sheldon with kids of his own, now looking back and realizing that maybe he didn’t understand his dad, or give his dad enough credit. So, it was really a nice way to bring that full circle.”

Holland said they had fun putting easter eggs around Sheldon’s office, for the future scenes.

“The ‘Big Bang’ set is in the Warner Brothers Museum here. And so, we went to the museum and started pilfering things that we wanted to take and stash in his office. That was an emotional moment…It was fun to pick out things that we thought Sheldon would keep that were important to him, and try to place them in a way that would be fun for audiences…maybe they could go back on a second viewing and freeze frame it.”

He cited Sheldon’s couch from “The Big Bang Theory” as “a big one.”

Holland added, “We wanted to make sure it wasn’t in the background of every shot. We thought people would just be distracted by it. So if you’re eagle-eyed, you can spot it.”

There’s also another “Big Bang Theory” spinoff show in the works about Sheldon’s brother, Georgie (Montana Jordan) and his wife, Mandy (Emily Osment), called “Georgie & Mandy’s First Marriage.”

Holland said it’s likely that Armitage will appear on it.

“It’s still early days, we haven’t shot anything yet,” he told The Post.

“Sheldon’s at Caltech, but that doesn’t mean he won’t ever come back for a holiday. We’re hopeful that this is a world where these characters can drop in, from time to time. It’s also important for us to make sure the new show has its own identity and isn’t just a parade of cameos.”

He added, “But, we definitely think there’s room in this show for this family to make appearances.”