About five minutes into the Monk episode "Mr. Monk and the Employee of the Month," lieutenant Randy Disher tells Monk’s assistant Sharona that he’s tired because he was up late with his new girlfriend.

"Yeah, well, those imaginary girlfriends can be pretty wild," Sharona jokes.

Defensively, Randy insists his girlfriend is not imaginary, so Sharona asks for her name.

"Crystal," Randy responds curtly, but behind him is a box labeled "Crystal Glassware."

Sharona smirks and retorts, "What’s her last name, Glassware?"

For true fans of classic TV, there’s a hidden layer of humor in this exchange.

Crystal Glassware references one of the most iconic jokes from The Brady Bunch.

In an episode called "The Not-So-Ugly Duckling," Jan Brady becomes devastated when her very first crush falls for Marcia instead of her. So, she does what any heartsick girl would do. She invents an imaginary boyfriend.

In the classic scene, Mike and Carol attempt to comfort Jan while she lays in bed pouting. When they tell her not to feel bad that she doesn’t have a boyfriend, she sits up.

"But I do have a boyfriend," she says, revealing he’s "one of the nicest boys in the school."

"That’s wonderful, Jan!" Carol says. "What’s his name?"

"His name… is George," Jan declares.

"George what?" Carol asks.

Jan’s eyes search the room and land on her nightstand where a drinking glass sits empty.

"George, uh, George … Glass!" Jan says, making the name up on the spot.

In the Brady Bunch episode, Jan’s secret comes out when Carol and Mike attempt to find George Glass to invite him to a party. During this detective mission, they discover he doesn’t exist, and they also realize that the boys in Jan’s class consider her "one of the guys" because she dresses like a tomboy.

The episode concludes with Jan showing up to the party in a cute dress and her first crush gaining new interest in her.

On Monk, Randy was known for coming up with ridiculous theories, but if you watch this scene between Randy and Sharona and sense some chemistry between the characters, you’ll be pleased to know the show did end up pulling that offbeat couple together in the end.

But the end of "Mr. Monk and the Employee of the Month" twisted away from The Brady Bunch by having Randy’s "imaginary girlfriend" Crystal actually be real.

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At the conclusion of the episode, Randy shouts for the whole office to look out the window where Crystal is waving goodbye from a cab.

But it’s too hard to see her clearly, so, unlike Jan whose fib is believed until she’s proven to be lying, no one believes Randy, even when he provides proof that Crystal really does exist.

This wasn’t the only time Monk referenced The Brady Bunch, though.

In the eighth season premiere, "Mr. Monk’s Favorite Show," Monk serves as bodyguard to a child star from his favorite show The Cooper Clan, obviously spoofing The Brady Bunch.

The episode references Brady Bunch episodes like "Confessions, Confessions," which solves the mystery of who broke Carol’s vase, as well as "Her Sister’s Shadow," which features Jan’s famous line "Marcia, Marcia, Marcia!"

On Monk, this line, of course, becomes "Adrian, Adrian, Adrian!"