Throughout “The Big Bang Theory,” we’re presented with three main romantic relationships. Leonard Hofstadter (Johnny Galecki) and his dream girl Penny (Kaley Cuoco) end in an up on-again, off-again relationship, and in season 3, wannabe lothario Howard Wolowitz (Simon Helberg) finally meets his match in Bernadette Rostenkowski (Melissa Rauch), a waitress who eventually gets her PhD and becomes a successful microbiologist. Sheldon Cooper (Jim Parsons) seems borderline allergic to romance in the early days of the series, but at the end of season 3, he meets Amy Farrah Fowler (Mayim Bialik), and the rest is history. Still, the show’s friendships are also a huge part of the narrative; Leonard and Sheldon are best friends, Penny and Sheldon end up growing unexpectedly close, and Howard and Raj are thick as thieves.

In Jessica Radloff’s 2022 book “The Big Bang Theory: The Definitive, Inside Story of the Epic Hit Series,” Helberg and Nayyar opened up about one of their duo’s funniest scenes, which takes place in the season 7 episode “The Deception Verification.” In it, Howard gets into his (always offscreen) mother’s estrogen cream and worries it’s making him “bloated” and “sensitive,” and as executive producer and writer Maria Ferrari explained, it was based on a real story from her family. 

“A relative of mine had been inadvertently touching this estrogen product and having this unexpected reaction,” Ferrari revealed to Radloff. “I was like, ‘This is hilarious, I think we can use it in a story,’ and Simon and Kunal are great. You could give them anything. They always committed and made everything better than you thought it was going to be.”

Apparently, Helberg thought it was incredible. “Any opportunity to touch Kunal’s nipples … contractually they had to adhere to that,” he said, laughing. Still, Helberg included a caveat, noting that the storyline might be a bit antiquated:

“So many of those jokes don’t age well, and a lot of them are promoting ideas we’ve grown past, but I also think there are still ways in which these things can be executed or written with a certain level of innocence that is coming from an actual, authentic character-driven place. It’s really funny and really hard to pull off, but the writers managed to go beyond some of that old-fashioned, familiar territory and get into a character-driven place.”

I’m sure you can guess what happens in “The Deception Verification,” which is that Howard, extremely worried that his mother’s estrogen cream is changing him, snaps at everyone, including Bernadette. Finally, he asks Howard to come over and asks him to see if his chest has gotten bigger, and the whole thing ends with the two men shirtless touching each other (with Bernadette looking on, embarrassed for everyone involved).

“In my memory, just getting to jiggle around with Kunal was a bucket-list item,” Helberg recalled. “And I got to be in sweatpants! Although now that I think about it, I did have to be shirtless and jiggle. You can’t have everything.”

As for Kunal Nayyar, he has several specific recollections about filming this particular sequence. “I remember being like, ‘Oh my god, I’m going to have to show my stomach and my chest,’ so I was doing crunches and all that sh**, trying to look slightly better.” Just to make everything better, Nayyar said that one small fact about the studio itself helped inform an acting decision. “The studio is always freezing, so during rehearsal, right before I had to grab Simon’s chest, I blew into my hands because they were cold,” he said. Nayyar elaborated:

“And they were like, ‘Oh, that’s brilliant! We have to keep that in there!’ And so we practiced that a lot, because otherwise I would just burst out laughing, which I did as well. I remember the scene being not that strange. Is it weird that we were so close it just felt normal? Raj was just always game to help. He was never weirded out by anything. It’s such an endearing quality.”

Right from the beginning of “The Big Bang Theory,” Howard and Raj are pretty much always paired up, so it makes sense that Simon Helberg said that he and Kunal Nayyar worked together beautifully. “There’s a dance that has to happen with scene partners, and it was always easy with Kunal because you just get the rhythm or you don’t. It’s chemistry. What Kunal and I had to do — which was slightly different because of Raj’s inability to speak in front of women for so long — was like a ventriloquist act.” (Here, Helberg is referring to Raj’s selective mutism around women early in the series; selective autism is a condition on the autism spectrum, but Raj’s form, which is only present when he’s confronted with the opposite sex, does appear to be a fictionalized approach.)

Nayyar agreed. “I was and am very close to Simon, and a lot of our banter offstage continued onstage,” he said fondly. “It never felt like work when we were in scenes together. It just felt like we were chilling somewhere. The hardest thing was breaking character, which I did all the time in my scenes with him. He is hilarious — and our friendship, as well as Raj and Howard’s — was a real joy for me.”

“We loved each other and we got really annoyed with each other, too,” Helberg chimed in. “We were kind of like brothers, and in some sense, this great divide between us, too, because we’re so different. But there was a real love in the center of it.”

Helberg, point in fact, was lucky enough to have two regular scene partners — Melissa Rauch and Nayyar — but he considered the two relationships to be completely equal. “He and Melissa were really the partners I had on the show for the majority of the run,” he said. “There was a love affair between Raj and Howard that I always took as seriously as you could take any relationship that’s built on love. I know there were a lot of bromance jokes and homoerotic jokes, but Kunal was like my first love.”

You can watch all of Howard and Raj’s “bromance” on “The Big Bang Theory” now, which is streaming on Max.