From a quirky song about a kitty to a character's secret smoking habit,
these are all the Big Bang Theory references you probably missed in Young Sheldon.
While watching Mary Cooper deal with the antics of her precocious, 9-year-old son,
first-time viewers of Young Sheldon might wonder how the show's creators managed to
cast someone who both looks and acts like Laurie Metcalf on The Big Bang Theory.
"I love the boy to death but he has been difficult since he fell out of me at the K-Mart."
As it turns out, the creators didn't have to look far — Metcalf's daughter, Zoe Perry,
filled the role. Fortunately for all involved, Perry's age just happened to align with the
timeline of the series, since Young Sheldon takes place roughly two decades before the
pilot episode of The Big Bang Theory. It's rare that actors get the opportunity to share a role
with one of their parents or children, so both Metcalf and Perry were thrilled with how things
worked out. In a 2020 interview with Backstage, Perry recalled the day she landed the role:
"I had already planned to have lunch with her and a friend the afternoon I found
out. I found out right before meeting with them, and then I got to tell them. We were
loud and boisterous in the restaurant for a second and then we calmed down."
Perry went on to add:
"It's been a cool experience getting to share this with her. She's been so great
and supportive along the whole path of this career I've embarked on."
In The Big Bang Theory canon, a man named Arthur Jeffries was the host of a children's science
show called "Professor Proton." Professor Proton inspired Sheldon to pursue a career in science at
a young age. But in the ensuing years, Jeffries became downtrodden, with his wife leaving him
for the puppeteer on his show. Ultimately, Jeffries became a reluctant party entertainer.
Introduced in a season six episode of The Big Bang Theory, Jeffries was played by legendary
comedian Bob Newhart. The role earned the comedy veteran an Emmy for outstanding guest
actor in a comedy series, and with repeated appearances, Newhart became a fan favorite.
Although he is now in his nineties, Newhart is still making people smile on television.
He appeared in a blink-and-you'll-miss-it cameo in the pilot episode of Young Sheldon
via the Professor Proton show. Newhart's character would also go
on to make two more cameo appearances in the first two seasons of the show.
"Professor Proton wears a bowtie!"
In a season three episode of Young Sheldon, Sheldon begs his dad George to take him to
Pasadena, California for a lecture conducted by the renowned physicist Stephen Hawking. Hawking
is one of Sheldon's idols, and the lecture takes place at Caltech. The mention of Caltech may perk
up the ears of die-hard Big Bang fans, as it will become the eventual workplace of the gang.
The ending of the episode makes a particularly poignant reference to the original show,
as Sheldon and George walk through the hallway of the institute. They
end their visit at the cafeteria, where Sheldon says with surety,
"I can see myself going here one day."
Surely enough, Sheldon will go on to graduate from Caltech and work there as a theoretical physicist.
The cafeteria is where the gang would often catch up during lunch, sharing many memorable Big Bang
moments. Though not always as intellectually stimulating as the young Sheldon may have hoped,
it nonetheless represents a very special place in the life of Sheldon Cooper.
Kaley Cuoco made a voice cameo appearance in a season three episode of Young Sheldon that
might be tricky to spot. After all, Cuoco isn't voicing her Big Bang character Penny,
and her name doesn't appear in the end credits.
In the episode, Sheldon is faced with having to attend a swim test
at school. Dreading the bacteria that rests in the school's swimming pool,
germaphobic Sheldon does everything in his power to avoid it, including faking an
illness. But his guilt over skipping school induces a nightmare. In it, the pool water,
voiced by Cuoco, entices Sheldon to come closer. The water promises that it's clean and hygienic,
but soon after gobbles Sheldon up. When Sheldon wakes up, he's both scared and startled.
Cuoco's presence in the episode is reminiscent of a running gag in The Big
Bang Theory where Penny would often frighten the neat-freak Sheldon with her messiness.
Adding to the plethora of ways The Big Bang Theory is a lot like Friends, there's a song
that gives Lisa Kudrow's "Smelly Cat" a run for its money: The similarly-cat-themed lullaby,
"Soft Kitty." When Sheldon was sick or sleepy on The Big Bang Theory,
he would have the person taking care of him sing the song, which is what his mother did
when he was a child. This running gag yielded several memorable moments in the series,
like the time an injured Penny asked Sheldon to sing to her.
Since Sheldon made repeated mention of his mother singing the song to him, it makes sense that it
appears frequently in Young Sheldon, making its first appearance in a season one episode. At the
end of the episode, Mary sings "Soft Kitty" to Sheldon on his bed when he has the flu.
For the socially-impaired Sheldon Cooper, one way to deal with difficulties in human
interactions is drawing up agreements and contracts for all involved. He does this
by removing ambiguity and clearly defining what each "party" is expected to do in a
given situation. One example came in The Big Bang Theory, when Sheldon made a roommate agreement
with Leonard. The agreement contained so many absurd clauses that it drove Leonard crazy.
The genesis of this tiresome trait is depicted in a season one episode of Young Sheldon. In
the episode, 9-year-old Sheldon gets the idea to draft a "relationship contract"
on his computer after his beloved Meemaw and her boyfriend Dr. Sturgis get into
an argument. The agreement clearly defines the bounds and limitations of their dynamic,
including a clause where Sheldon isn't allowed to spy on Meemaw's house with his binoculars.
Keeping mental notes of one's grudges can be both tiresome and draining — especially for
Sheldon Cooper. After all, he'd rather preserve his mental energy for more important pursuits
in life such as science, physics, and countless hours of comic-book reading. So what is Sheldon's
solution? A list of his "mortal enemies," kept on a five-and-a-quarter-inch floppy disk.
Some of the noteworthy individuals who are unfortunate enough to be included on
the list include Wil Wheaton and Batman & Robin director Joel Schumacher. According to Sheldon,
Schumacher is on the list for, quote, "nearly destroying the Batman franchise."
The presence of the floppy disk and a few other clues have always seemed to imply that
Sheldon has been maintaining this list since the late 1980s/early 1990s — essentially,
his childhood. This was confirmed in a season one episode of Young Sheldon. In the episode, Sheldon
falls in love with a computer he spots at a local Radio Shack, particularly for its ability to
"easily alphabetize" his list of enemies and their transgressions. The computer ultimately becomes a
focal point for the episode, with Sheldon sparking a heated disagreement between his parents about
their finances. This all happens after Sheldon asks his mom and dad to buy him the computer.
"If you switch to Hawaiian punch we can live in a bigger house."
One of the most unsettlingly iconic images in The Big Bang Theory was that of a Gollumized
Sheldon scaring himself in the mirror. In the episode, Sheldon wages a war against Leonard,
Raj, and Howard over a prop ring officially used in The Lord of The Rings movies. Needless to say,
it was both funny and creepy. After his three opponents copped out, Sheldon found himself as
the sole possessor of the ring. So, as he goes to the bathroom to clean it, Sheldon
looks up in the mirror to see that he has turned into Gollum. Of course, it's only a nightmare.
Young Sheldon revisited the moment in a season three episode. In the episode,
Sheldon reads up on Tolkien's Lord of the Rings books. His reasoning for this is pretty simple:
"I'm just looking to take a break."
Science, of course, is what he's needing a break from. Similar to his older self, Sheldon becomes
so engrossed with the fantasy world of the series that it invades his dreams — and in
a Gollum-like moment of split indecision, he argues with himself. Clearly, Gollum is the
best pop-culture character to personify Sheldon's inner demons, both as a child and as an adult.
In The Big Bang Theory, Sheldon firmly establishes his mom as:
"A kind, loving, religiously fanatical right-wing Texan
with a slightly out of scale head and a mild Dr. Pepper addiction."
In a season two episode, a half-asleep Sheldon also revealed that his mother
had a secret smoking habit during his childhood.
"Mom smokes in the car. Jesus is okay with it, but we can't tell Dad."
Sure enough, Young Sheldon has Mary secretly reaching for a cigarette
whenever she's tense. The first instance of Mary smoking was shown in a season
three episode. Sheldon gets an offer letter from Caltech in the episode,
so a distressed Mary lights up over the possibility of her 11-year-old leaving the nest.
Mary is also seen smoking in a season five episode of Young Sheldon. In the episode, Marital problems
threaten George and Mary. But when George comes home to patch things up with his wife, he finds
Mary bonding with Pastor Rob over a smoke. Sheldon's strict adherence to a bathroom schedule,
and its inclusion in his roommate agreement with Leonard, reliably caused irritation throughout
The Big Bang Theory. The printed timetable hung on the refrigerator in Sheldon and
Leonard's apartment became a bone of contention between Sheldon and Leonard's then-girlfriend
Priya. While acting as Leonard's lawyer in a season four episode, Priya successfully
nullifies several clauses in the roommate agreement — including the bathroom schedule.
But it appears that Leonard wasn't the only one to bear the brunt of Sheldon's
timetable. In a season one episode of Young Sheldon, Mary details Sheldon's bathroom
schedule to George just before he takes his 9-year-old son on a trip to Cape Canaveral.
The schedule also received a shout-out in a season three episode of the show.
In that episode, George is once again taking his son on a cross-country trip,
and shudders at the thought of having to deal with the boy's bathroom schedule in
a different time zone. The infamous timetable then appeared in the flesh in a season five episode. In
that episode, an image of the schedule was displayed over adult Sheldon's narration.