'Big Bang Theory' Creator Chuck Lorre Explains the Series Finale's Sweet Last Scene

"It all started with the big bang."
Courtesy of CBS

[This story contains spoilers from the series finale of CBS' The Big Bang Theory.]

It all started with the big bang — and it ended that way, too.

CBS' The Big Bang Theory closed up shop Thursday with a sweet, funny and emotional series finale that also featured a bit of closure for co-creator Chuck Lorre.

The final scene of the two-part series ender featured the gang gathered in Leonard and Penny's living room for Chinese food in a scene set to a new version of the show's now-iconic theme song, performed by Barenaked Ladies.

As it turns out, the song in the scene — which was filmed on a closed set to allow the cast to share the special moment together with the creators and crew — was something Lorre wanted to do way back during Big Bang Theory's development stages.

"Twelve years ago, [Barenaked Ladies lead singer] Ed Robertson sent a demo of that theme song — just him and an acoustic guitar. I thought it was great and I said, 'That's our theme song.' He said, 'No, we're a band, we do everything as a band. We have to re-record this as a Barenaked Ladies song with the whole band."

Lorre wound up relenting — a point he now says, in hindsight, was the right decision — and the the song, dubbed "History of Everything," became synonymous with Big Bang Theory for diehards.

"I always loved that acoustic version," Lorre says of the song that started out as a demo. "I called Ed a month or so ago and asked him if he would consider re-recording an acoustic version, slowing it down, singing it out of time so that it's somewhat free of a time signature and use it for the last scene just over the characters having dinner. We went in the studio and recorded it and it was perfect."

The band would wind up performing the eventual theme song live at the show's San Diego Comic-Con panel back in 2010 that featured a packed ballroom of thousands singing along in unison. (Watch that performance, below.)

"One of the gifts of being part of this series all these years was Ed Robertson, and the Barenaked Ladies have just given us an enormous boost," Lorre says. "That theme song gives you such a good feeling at the beginning of every episode. It's a remarkable little piece of music. I defy anybody to listen to that song and not smile."

Lorre added that using the concept for the original song was an important part of the series finale, which wound up focusing on the characters' "emotional closure" rather than sending everyone off in different directions and wrapping the show up with a big bow.

"I just thought maybe it would be appropriate to go back to that acoustic version, slow it down, imbue it with a melancholy mood and take us out and that be our last piece of the finale," Lorre said.

Watch the scene, below. Click here to read THR's interviews with the producers and here for the cast's thoughts on how their respective journeys ended.