Despite its success and longevity, things weren't looking good for The Big Bang Theory early on. Although Chuck Lorre was attached to the project, major changes were constantly being made to the script, and that included the removal of major characters.

Finally, once the cast was set, the show took off and enjoyed success not even the main characters could've predicted. However, as we'll reveal, the main cast could've looked extremely different at the start, with a major name attached to the series.

We'll take a close look back at why this popular actor turned down the role - and how he felt about the cast making millions down the road. Despite the missed opportunity, the actor does not seem to be bothered one bit.

Jim Parsons Nailed His Audition For Sheldon But Admits His Monologue Was Not Easy To Memorize

jim parsons big bang
A photo of Jim Parsons speaking along with Kaley Cuoco, Johnny Galecki, Kunal Nayyar and Mayim Bialik in the background. 
via: Instar

Jim Parsons nailed his audition for The Big Bang Theory, so much so that Chuck Lorre wasn't entirely sure that the actor could've duplicated the performance on-set if he got the job.

Thankfully, the showrunners had faith in his abilities from the start. However, the actor did reveal that the audition process was not an easy one, especially given the dense script he was forced to memorize at the start. During the early portion of the show, Sheldon's lines were complex, to put it mildly.

The actor recalls his nervousness during the audition, "I worked my ass off on it! You have no idea how well memorized I was. Sheldon has so much to say sometimes — it's not as bad as it used to be — and it was really dense and it was clear to me that the humor that was built into this was only if these dense pieces flowed very easily. I drilled the shit out of it! I was very scared — and excited to present it to them," he tells THR.

RELATED - The One Big Bang Theory Actress That Played Two Different Roles During The Show's Run

Parsons got through the first part without any type of hiccup. He expected the second part to be saved for a callback. However, he was asked to present it on the spot.

After taking a moment outside, the actor got it together and nailed it as well. At that point it was evident, the search for Sheldon had come to an end.

Macaulay Culkin Was Pitched The Big Bang Theory At The Start, And Knows He Missed Out On Millions

Is Macaulay Culkin Extremely Strict With His Son Dakota After His Scandalous Experience Being A Child Star_
Macaulay Culkin family children
Via: TheThings

Back in 2018 on the Joe Rogan Experience podcast, Macaulay Culkin made a major reveal. According to the child star, his career almost took a major turn due to a proposal given by CBS. Attached to the script was Chuck Lorre, a man actors rarely turn away from.

Not only did Culkin reject the offer, but he revealed that they kept coming back despite his disapproval.

“They pursued me for The Big Bang Theory,” Culkin said on the podcast.

“And I said no. It was kind of like, the way the pitch was, ‘Alright, these two astrophysicist nerds and a pretty girl lives with them. Yoinks!’ That was the pitch. And I was like, ‘Yeah, I’m cool, thanks.’ And then they came back at me again, and I said, ‘No, no, no. Again, flattered, but no.’ Then they came back at me again, and even my manager was like twisting my arm.”

RELATED - How Jim Parsons Really Felt About His Intimate Scene With Kaley Cuoco On The Big Bang Theory

Culkin is aware he missed out on millions, especially given that the core cast made $1 million per episode in the final seasons. Nonetheless, creatively, he showed no regrets.

“I’d have hundreds of millions of dollars right now if I did that gig,” Culkin said. “At the same time, I’d be bashing my head against the wall.”

Although he didn't opt for the role, it would've been great to see the actor perform a cameo for the series.

Jim Parsons Turned Into The Highest-Paid Actor On Television, While Others In The Cast Climbed To $1 Million Per Episode

The Cast of The Big Bang Theory on CBS The Early Show Instar

Back in 2017, Forbes issued their list of highest-paid TV actors in Hollywood. Culkin might've turned away from that list at the time, as it was dominated by The Big Bang Theory cast. In fact, Jim Parsons was number one on the list, bringing in a huge salary of $27.5 million, which was also aided by his huge endorsement deals, such as a partnership with Intel.

RELATED - Billy Bob Thornton Had A Specific Condition About Working With Kaley Cuoco On The Big Bang Theory

Despite Jim's obvious success on the show, he couldn't have predicted that type of success - even if he though Sheldon was a unique character and unlike anything he'd ever seen.

“When I read Big Bang it was definitely special to me. I would definitely not presume to say I thought it was going to be a hit show or be picked up, but I know that I was being presented with a character that was, in its own weird way, a really good fit, that I thought I could do."

Oh, how different things could've been looking back had Culkin been attached to The Big Bang Theory.