Chuck Lorre and Bill Prady took sitcoms on a wild ride in 2007 with the successful release of the hit series The Big Bang Theory. Sheldon (Jim Parsons), Leonard (Johnny Galecki), Penny (Kaley Cuoco), Raj (Kunal Nayyar), Howard (Simon Helberg), and later Amy (Mayim Bialik) and Bernadette (Melissa Rauch) brought humor and heartfelt moments across an impressive twelve seasons, with the series transitioning from a comedy about nerds to a coming-of-age series for the characters. In 2017, The Big Bang Theory fans were delighted to learn that a prequel spin-off, Young Sheldon, had been green-lit, providing the backstory of the eccentric Sheldon Cooper and the origin stories of his peculiar ways. Iain Armitage stars as the younger version of Sheldon, who lives in Texas with parents George (Lance Barber) and Mary (Zoe Perry), older brother Georgie (Montana Jordan), and fraternal twin sister Missy (Reagan Revord).

Young Sheldon fills in the gaps in Sheldon’s life across six seasons, with one more set to release in 2024. The shows are intrinsically tied to each other; from casual easter eggs and name drops to long-running character arcs that explain Sheldon’s psyche, The Big Bang Theory and Young Sheldon have plenty of things in common. These are the 10 most memorable connections between The Big Bang Theory and Young Sheldon, from the obvious ones everyone can see to the ones only hardcore fans will notice.

10.Soft Kitty

“….warm kitty, little ball of fur.”

Young Sheldon immediately explores Sheldon’s germaphobic nature, and in “A Sneeze, Detention, and Sissy Spacek,” he goes to extreme measures to avoid the flu as it passes through Medford. But, when he inevitably catches the flu, fans are treated to the first time that “Soft Kitty” is sung.

The Big Bang Theory first made “Soft Kitty” popular when Penny sings it to a sick Sheldon in an episode from season 1. The prequel shows the tender moment when Mary sings “Soft Kitty” to Sheldon to make him feel better, thus explaining his warm feelings toward the song. “Soft Kitty” is a pretty funny song, but over time, it became more meaningful as a bonding moment between Sheldon and his friends, especially Penny.

9.The Relationship Contract

Sheldon Loves to Draft Them… Not Just for Himself!

The Big Bang Theory viewers are well aware of Sheldon’s well-thought-out, detailed agreements — from the roommate agreement with Leonard to his relationship agreement with Amy. Becoming a somewhat running gag within the series, Sheldon’s extensive rules are put into place for his comfort and guidelines while attempting to understand the framework clearly.

In the Young Sheldon episode “Vanilla Ice Cream, Gentleman Callers, and a Dinette Set,” Sheldon becomes invested in the relationship between his Meemaw and Dr. Sturgis (Wallace Shawn), where he creates his first-ever relationship agreement to regulate their relationship. Sheldon’s love for order and audits is among his most recognizable trademarks, so seeing him develop his tendency to draft relationship contracts is both endearing and hilarious.

8.Professor Proton

Played by TV Legend Bob Newhart

A link between the younger Sheldon and his adult self is his unrequited love for Professor Proton (Bob Newhart), one of the best side characters in The Big Bang Theory. Professor Proton was first introduced in The Big Bang Theory as Leonard and Sheldon’s childhood hero, a science show host who first made them want to pursue the science field.

In Season 6, the friends learn that the retired entertainer is available for parties and are shocked to discover that he doesn’t love his Professor Proton image as much as they do. Arthur Jeffries – Proton’s real name – appears in other episodes within the series, eventually dying in season 7 but returning as a “force ghost” in Sheldon’s dreams. Young Sheldon showcases Sheldon’s love for Professor Proton’s show, with many arguments with his family over his educational show over mindless entertainment, as well as a signed poster in his bedroom.

7.”Bazinga!”

Sheldon’s Trademark Expression

Sheldon has many memorable episodes in The Big Bang Theory. However, the most memorable chapters usually have him saying his catchphrase, “Bazinga!” Sheldon uses it as a punchline to his numerous and often clumsy jokes, which no one but him finds funny.

In Young Sheldon, “Bazinga” is finally given an origin story in Season 2, episode “A Stunted Childhood and a Can of Fancy Mixed Nuts.” After relentless teasing by Missy and Paige (Mckenna Grace), Sheldon sets out to prove he has a childish side, where he buys joke pranks from a brand called “Bazinga.” Because Sheldon is extremely literal, he immediately relates the brand’s title to humor as a whole, thus utilizing “Bazinga” as his general catchphrase.

6.The Nobel Prize

Sheldon’s Ultimate Goal

The biggest crossover between both shows occurred as two episodes aired back-to-back: the last episode of The Big Bang Theory, “The Stockholm Syndrome,” and the Young Sheldon season 2 finale, “A Swedish Science Thing and the Equation for Toast.” In The Big Bang Theory finale, fans are delighted to see Sheldon and Amy be awarded for their contributions to science with a Nobel Prize, where Sheldon recognizes his friends, family, and Amy for their love and support.

In the Young Sheldon episode, Sheldon invites the entire school to a listening party to hear the announcement of the latest winners of the Nobel Prize, but his happiness diminishes when no one shows up — not even his mentor, Dr. Sturgis. In a voiceover, Sheldon admits that he had never felt so alone but reflects on the fact that he would one day be surrounded by friends. During this ending, a montage of younger versions of The Big Bang Theory cast is shown. These two episodes draw a beautiful and satisfying bridge between Sheldon’s past and present, cementing how, despite his goal-oriented mind, he still craved companionship.

5.CalTech

Sheldon’s Place of Work

In The Big Bang Theory, Sheldon, Leonard, Raj, and Howard attend CalTech — a private research university in Pasadena, California. Many episodes are filmed in that location, showing the research each character is working towards and their fights — particularly in the cafeteria.

In Season 3, Episode 16 of Young Sheldon, Sheldon and George head to Pasadena to attend a lecture by Stephen Hawking. Sheldon reflects on the university and, in the final scene, is shown looking into the cafeteria, where he will sit with his friends in the future. It’s a nice reference to the place where Sheldon would spend so much of his time and yet another hint at the promising future that awaits him.

4.The Bathroom Schedule

His Vowel Movements Run Like a German Train Schedule

One of the more obscene aspects of Sheldon Cooper’s personality is his regimented bathroom schedule. Outlining specific timeframes that the bathroom will be occupied by him every day of the week, the bathroom schedule caused tension between himself and Amy when they finally move in together in The Big Bang Theory and endlessly irritated Leonard and Penny.

In Young Sheldon’s “Cape Canaveral, Schrödinger’s Cat, and Cyndi Lauper’s Hair,” Sheldon’s bathroom schedule becomes a bonding moment between Sheldon and George Sr. Taking his sons on a trip to see a spaceship launch, George is grilled by Mary about his supposed inability to take care of Sheldon properly. When he successfully recites Sheldon’s bathroom schedule, fans realize that George pays a little more attention than originally thought. George unexpectedly became one of the most likable characters in The Big Bang Theory, and it’s thanks to little details like this one.

3.A Hot Beverage of Comfort

Tea for When He’s Sad

One of the softer sides to Sheldon is his attempts to comfort people he cares about. While he may not always have the right words, he learned to offer people a hot beverage of comfort from a young age. In The Big Bang Theory, the first person Sheldon offers a hot beverage to as comfort is Leonard in the Season 1 episode “The Middle-Earth Paradigm.”

Young Sheldon explored the origin of his method in “Body Glitter and a Mall Safety Kit.” When he realizes Paige isn’t dealing well with her parents’ divorce, he offers her a cup of tea when she cries. George walks in on his son making the tea and tells him he is proud of him. Young Sheldon proves how much of a creature of habit Sheldon is, to the point where the things he learned as a child carry on to adulthood with little to challenge his beliefs.

2.George’s Fate

Sheldon’s Dad Will Have a Tragic End

Fans are led to believe Sheldon’s relationship with his father was never particularly close, especially compared to his and Mary’s relationship. However, Young Sheldon proves that George Sr. and Sheldon had a deeper, closer bond than anyone thought, with the former proving himself a surprisingly reliable presence in the latter’s life.

Fans of The Big Bang Theory will know that Sheldon’s dad passed away when he was fourteen from heart complications, with Georgie feeling like he had to take care of the family as the next man of the house. With season 7 announced as Young Sheldon’s last, it’s not difficult to realize the show will probably end with George’s death. It will surely be a bittersweet moment for fans everywhere, but at least the show has done a lot to improve George’s reputation among the Big Bang community.

1.Sheldon & Amy’s Future

Parents to a child named… Leonard!

In The Big Bang Theory, fans were delighted when Sheldon and Amy married in the season 11 finale. Watching the growth of Sheldon falling in love, being intimate, and learning to compromise was the highlight of the series.

After The Big Bang Theory, fans were left in the dark about the success of “Shamy,” but Young Sheldon luckily shed light on their current situation. During “Graduation,” adult Sheldon reflects that his high school graduation party was the best one he had ever attended, asides from his son’s. Sheldon’s voiceover then reveals that their son is named Leonard, after his best friend and roommate and, of course, Leonard Nimoy. He teases that his son’s name should’ve been Leonard Nimoy Cooper, and Amy quips back that he is lucky that the name Leonard got chosen.