Looking back, The Barenaked Ladies set the tone for right from the start with their iconic theme song. Although the group hesitated at first, they made the right decision to take on the opening song. The result,

However, negotiations at the start weren't that smooth and in fact, Robertson refused to use his rough version for the show despite Chuck Lorre's request. We'll take a look at why Ed turned down the request, and how the initial version was still used for one of the show's most important episodes.

The Barenaked Ladies Almost Rejected The Big Bang Theory

Given his history with TV and film projects, . The frontman had lots of work that never made it onto the air, and didn't want to repeat this formula once again. However, his agent kept nagging about the opportunity, while his wife also encouraged him to take on such a project, especially given the potential.

Robertson revealed with "I mentioned to my wife that I had a conference call with this song that I hadn’t been able to write, and she asked who the call was with," Robertson said. "I told her it was Chuck Lorre, and she was like 'you should Google him.' So I did and was like 'oh, s***, this might be real.

"

Robertson then realized after a call with Chuck Lorre that he wasn't competing against anyone else for the gig. Within five-minutes during a shower, Robertson had come with the entire song and as they say, the rest is history. Well... not so fast.

Ed Robertson Sent An Acoustic Version But Refused To Use It Because It Didn't Involve The Barenaked Ladies

We throw it back to the start of , even before the show was underway for this particular moment. Ed Robertson sends Chuck Lorre a rough version of the song, which happens to be an acoustic alternative.

Lorre fell in love with this version - however, it wasn't what Robertson had in mind. given that it didn't include the rest of the Barenaked Ladies.

Lorre tells , “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.”

The song was altered with the entire group, and there's really no denying the success and impact.

Lorre went on to reveal, “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.

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.”

Not only was the song a hit, but the acoustic version wasn't scrapped, and used during the show's most important episode.

The Big Bang Theory Ended Up Using The Acoustic Version For The Finale

Upon Chuck Lorre's request, T theme song using its acoustic version was revived for the finale, and what a moment it turned out to be. Lorre was granted the request, and it made the finale that much more special.

“I always loved that acoustic version.

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.”

“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.

Lorre was spot on with his vision, while .

"It’s been like having a hit multiple times a year for over a decade.

It’s been life-changing. The song has been very good to me,’ he continued. ‘And to my family. And to my grandchildren’s family."

"That song changed my life,’ he reflected. ‘The writing process was so fun and easy and rewarding and my relationship with [TBBT creators] Chuck Lorre and Bill Prady has been so cool over the years. They’ve been so supportive of the band, and it changed my life unlike any other song in my entire catalogue."

A great piece of business for both sides.