The Big Bang Theory wrapped up after 12 seasons in the only way it could: Bernadette (Melissa Rauch), Howard (Simon Helberg), Leonard (Johnny Galecki), Penny (Kaley Cuoco), Sheldon (Jim Parsons), Amy (Mayim Bialik) and Raj (Kunal Nayyar) hung out in their living room, talking, giggling and eating takeout. The Thursday, May 16, episode was emotional, to say the least.
However, over the talking was an acoustic version of the series’ theme song, “History of Everything,” usually sung by Barenaked Ladies. However, the ending was just frontman Ed Robertson singing — a version that cocreator Chuck Lorre always wanted to feature.
“Twelve years ago, 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 rerecord this as a Barenaked Ladies song with the whole band,'” the producer, 66, explained to The Hollywood Reporter.
He added: “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.”

To top it off, the cast joined The Late Show With Stephen Colbert for an interview and then, the two-time Grammy nominees performed.
“I was really honored that they asked me to participate in the finale,” Robertson said in a statement. “It was a really fun and collaborative day in the studio, getting notes back and forth from Chuck while coming up with this new version. It really reminded me of composing and recording the song in the beginning — fun, spontaneous, and with a spirit of playfulness.”
He continued: “Our association with the show is something we’re all very proud of, and being involved in so many fun ways as the show draws to a close is really cool. The chance to play the song on The Late Show with the whole cast present is a lovely bookend to an incredible run.”
The final scene also included “ad-lipping” from the cast. “There were so many technical things happening, I think it kept it from getting overly emotional, even though they knew it was going to be the last scene,” EP and cocreator Bill Prady told Glamour. “Penny is wearing the top she wears when she first appears on-screen in the pilot, which was really cool. And then it’s nice to see Amy and Sheldon wearing their Nobel medals.”