EXCLUSIVE: The Surprising Secret Behind 'The Big Bang Theory's Most Romantic Moments!

by Leanne Aguilera 12:15 PM PST, February 12, 2015
Photo: CBS

From spur-of-the-moment proposals, to sneak-attack I love you's, The Big Bang Theory sure knows how to tug-on-our heartstrings.

It might have started off as a quirky show featuring four brainiac scientists, but over the last eight years the CBS comedy has consistently surprised fans with some of the most romantic moments in TV history.

To get the inside scoop on to these sly, yet swoon-worthy moments, ETonline recently caught up with executive producers Bill Prady and Steven Molaro, and we discovered that your favorite BBT moments often come as a just as much of a shock to writers as they do to the audience.

NEWS: Why This Episode of 'Big Bang' Could Be Our New Favorite!

"These things always come out organically," Prady said of the big romantic gestures on the show. "I think that one of the things that makes The Big Bang Theory couples work is that, from a writing point of view, it's not written with the result first."

"They sneak up on us as we write," he continued. "It always starts from here's something that's going on in our characters' lives, and how would that effect the characters. And from that, how would that affect their relationships?"

One of the most recent massively tear-jerking moments happened in November's episode "The Prom Equivalency" when Sheldon (Jim Parsons) shocked audiences by saying "I love you too," before Amy (Mayim Bialik) could even muster up the courage.

WATCH: What's Next For Your Favorite 'Big Bang' Couples!

"I cried too," Molaro said of the sweet Shamy surprise. "I get very emotional with these scenes. I think what in particular touches me about that scene is as amazing and wonderful Sheldon actually is before he admits it, it's how nervous Amy is trying to get herself to say the words."

The EP continued, "When she's in that moment of, 'You don’t have to say it back, and I don’t want you to feel any pressure,' I'm so there with her, and that's where I start to get choked up. Then he says it first and their first 'I love you' is actually 'I love you too.'"

The powers-that-be at Big Bang are not ones to force a special moment. It's all about subtlety building up to that long-awaited moment -- like when Leonard (Johnny Galecki) finally proposed to Penny (Kaley Cuoco-Sweeting).

"We'll have an idea that's what we're aiming for, but how it's going to be executed and how the final words come out and it's usually a surprise," Molaro explained. "It was very last minute when we figured out that Leonard had that ring in his wallet."

NEWS: How 'Big Bang' Surprised Fans With Billy Bob Thornton!

In the penultimate episode of season seven, Penny and Leonard's spur-of-the-moment, Pop-Tart metaphorical proposal was made even sweeter when Leonard pulled out a diamond ring from his wallet. "Where did you get a ring?" Penny asked with a stunned whisper. "Uh, I've had it for a couple years," Leonard quickly stumbled. "Not important."

And apparently that so-sweet-it-hurts moment almost never happened! "That was very last minute," Prady confessed. "It came up from a conversation of, 'It would be really great in this moment if he had a ring' and then we said, 'Well what if he had a ring?'"

Molaro explained that this last minute scene-addition happened just days before the episode. "We started shooting that episode on a Monday and that was Friday afternoon before we finally stumbled onto that sweet little moment," he said. "As soon as it came up we thought that was the way to go."

WATCH: 'Big Bang' Cast Goes to Prom! See Their Old High School Photos

Although it's the writers who pen these heartfelt moments, both Molaro and Prady attribute the magic to the stars of the series. "We’re just lucky that we have these seven actors who are so incredibly talented and there's so much actual love between them that you can feel it," Molaro explained. "And they're able to take these scenes that we write and make them real and make them better."

So what's next for all of your favorite beauty and the geek couples? Molaro teased, "Everyone is moving forward in some way, but even we don’t know exactly where they're headed until it happens." The Big Bang Theory airs Thursdays at 8 p.m. on CBS.

Which romantic Big Bang Theory moment has been your favorite? Shout out your thoughts to @LeanneAguilera on Twitter using #ETNow.