After Mayim Bialik joins “The Big Bang Theory” in the show’s third season as Amy Farrah Fowler, a neuroscientist who ends up romancing and marrying the prickly Sheldon Cooper (Jim Parsons), it’s legitimately hard to imagine the show without her presence.

Here’s something funny, though: in the show’s very first season, “The Big Bang Theory” obliquely references the real Bialik, though it doesn’t say her name (which was probably sort of helpful for continuity later on, whether the show intended for that to happen or not).

In the season 1 episode “The Bat Jar Conjecture,” Sheldon and his friends and fellow California Institute of Technology colleagues Leonard Hofstadter (Johnny Galecki), Raj Koothrappali (Kunal Nayyar), and Howard Wolowitz (Simon Helberg) are gearing up to participate in the university’s annual Physics Bowl, but true to form, Sheldon makes all of his friends so irritated that they kick him off the team.

(This is largely because Sheldon is convinced he doesn’t even need teammates and can simply win the entire thing himself.)

While the rest of the guys are trying to figure out how to replace Sheldon, Raj comes up with a suggestion: “You know who is very smart is the girl who played TV’s ‘Blossom.'”

“After that, he says the actress has a ‘PhD in neuroscience or something.'”

That, of course, is Bialik, mentioned at a point when the show’s creative team had no idea she’d ever appear on the series. So, how did Bialik become a core part of the cast of “The Big Bang Theory?”

In Jessica Radloff’s book “The Big Bang Theory: The Definitive, Inside Story of the Epic Hit Series,” the show’s cast and creative team opened up about the entire series … including how they managed to snag Mayim Bialik for such a pivotal role.

“There was always a desire to have more female scientist representation because it was a very male-heavy show,” executive producer and writer Steve Holland told the writer.

“It wasn’t a thing where we were like, ‘We’re going to write this character and have her be a part of the show,’ but it was a thought that this was important for us to do.

[Creators Bill Prady and Chuck Lorre] wanted to highlight women in science as well, but it had to be the right role.”

Ultimately, Holland said that Bialik’s real-life expertise simply informed the role: “I think Amy only turned out to be a neuroscientist because we cast Mayim and she was a neuroscientist in real life. In fact, in the episode where we first meet her, I don’t think we ever say what she does. It just became a matter of writing to these characters’ strengths.”