NBC

Kaley Cuoco Had A Secret Cameo On 'Young Sheldon'

Updated September 7, 2021

Kaley Cuoco may have wrapped up The Big Bang Theory last year, but that doesn't mean that her time annoying Sheldon is over.

The actress just made a secret cameo on Young Sheldon!

It's been almost a year since "The Big Bang Theory" ended.

The popular CBS sitcom followed the lives of four nerdy friends, Sheldon, Leonard, Raj, and Howard, whose lives were never the same after they met the beautiful Penny next door.

That was just the original cast; new characters were added as storylines expanded.

IMDb

For example, Howard got married to Bernadette, Leonard married Penny, and even Sheldon eventually got married to Amy Farrah Fowler, a neuroscientist.

A prequel of the series called "Young Sheldon" started before the show even ended.

NBC

The series, which allowed fans to see Sheldon and all his quirks as a kid, premiered in 2017.

And now, it's been discovered that a December 2019 episode even featured a "Big Bang Theory" crossover!

Instagram | @kaleycuoco

Kaley Cuoco (who played Penny on The Big Bang Theory) lent her voice for the December 12 episode, entitled "Teenager Soup and a Little Ball of Fib."

In it, Sheldon (Ian Armitage) has a nightmare over having to go into a bacteria-infested pool for an impending swim test in gym class.

Flickr | @HollywoodMeraki

This results in Sheldon talking to the pool at some point.

When he does, it's Cuoco's voice that speaks back, surprising fans.

The series co-creator, Steve Molaro, recently explained how Kaley's secret cameo came to be.

“That was absolutely the voice of Kaley as pool water. I needed someone to do the voice. I knew I wanted it to be female and kinda sexy, and I said, ‘Well, duh! Kaley is perfect for this.'”

He soon pitched the idea to Kaley.

Instagram | @kaleycuoco

“I said, ‘Hey, I have a weird pitch for you: Sheldon has a nightmare, and he has to go to this pool, and he speaks to the pool water. Do you want to be the voice of pool water?'” Molaro recalled.

“She just laughed and said, ‘Absolutely, I do.'”

Since her role would be so small, though, they questioned whether a) they should promote her cameo at all and b) whether they could really call it a "crossover" to begin with.

“Sometimes I feel a little weird about things being over-promoted,” Molaro said.

“And as awesome as it was, I don’t know that that should be the kind of thing that appears in promos."

"[Kaley] wanted to hold it under wraps [as well], so that if you figured it out, that was a little Easter egg for you, so we were all on the same page about that.”

Very sneaky!

Cuoco isn't even the first The Big Bang Theory character to crossover to the series.

Jim Parsons, who plays adult Sheldon, works with the show on a permanent basis.

He's an executive producer on Young Sheldon and even narrates the series.

Here he is with Iain on "The Ellen Show," talking about what it's like for Iain to play a young Sheldon.

During a February 20 episode of the show, titled "Pasadena," 10-year-old Sheldon is even going to Southern California to visit the California Institute of Technology, where adult Sheldon spends most of his time.

But the crossovers don't stop there. In the final season of "The Big Bang Theory," Sheldon even met Young Sheldon on the show!

This is toooo adorable!