Kaitlin Olson's Real Life Pregnancy Made One It's Always Sunny Scene Extra Difficult

"It's Always Sunny in Philadelphia" has some hilarious dialogue, but the physical comedy is a huge highlight of the series. From Frank falling out of a window to Dee's constant retching, some of the most memorable moments of the show are totally silent. Charlie Day might have starred as a silent comic in "Fool's Paradise," but the real slapstick artist of the group is Kaitlin Olson, who plays the intolerable Sweet Dee.

Olson has proven time and time again that there's no line she won't cross for a good joke, even if it means putting herself in physical danger. In fact, one of Dee's biggest moments of physical comedy was filmed while Olson was well into her first pregnancy — and it may have caused some permanent damage to her stomach.

The "Curb Your Enthusiasm" actress joined the "Sunny" cast when it was picked up for series by FX and immediately made some changes to her character. Originally written as the nagging straight woman in a group of unruly men, the comedian insisted that her character be just as outrageous as the rest of the gang.

"Let the world be the voice of reason, and let us be ridiculous," she recalled telling her co-stars in an interview with Entertainment Weekly.

Dee also quickly became a highly physical character. She sports a neckbrace in the season 2 premiere and a metal back brace in the season 3 episode "The Aluminum Monster vs. Fatty Magoo." The corporal comedy of her character was inspired by Olson herself. "Our idea of Dee was not as physical as Kaitlin is," her husband, co-star and showrunner Rob McElhenney told Buzzfeed. "It's something we sort of found with the way she carries herself."

In the season 4 episode "Who Pooped the Bed?" Olson performed a stunt so dangerous that she could have left herself severely injured. Dee runs out of a shoe store in an ill-fittting pair of heels and takes a fall, slamming her head into a car door so hard it leaves a dent. Doing her own stunts is a huge risk, but its part of what makes Dee's physical comedy so distinct. Olson is acutely aware of this, and so are her collaborators.

"We had a stuntwoman do it, and it didn't look very real, and then Kaitlin did it, and actually ran into the car, probably almost breaking her neck," Day added. "It's just one of the funniest moments of physical comedy I think in the history of the show."

Perhaps the most unforgettable moment of Olson's physical comedy in "Sunny" is her impression of an inflatable man in "The Gang Buys a Boat." This praise was hard-earned, the "Hacks" actress assured Elle — she filmed the scene six months pregnant:

"I love how much people have responded to that episode. I get tweets every single day about it. I love it so much because I worked so hard mimicking that thing. And I was six months pregnant and trying to hide it. It was 3 a.m. out on a boat in Long Beach. It was freezing cold, and I was so tired. I remember being so angry that because I was pregnant I couldn't bend backwards as far as I wanted. I just kept trying harder and harder and that stupid baby wouldn't let me do it. I'm pretty sure I ripped my stomach muscle moving like that. That's what I can thank for ruining my stomach. But I worked so so hard on that dance and I think it ended up looking fantastic."

Olson's goofy movement was a frequent source of inspiration for her husband. McElhenney reshaped the character to incorporate his wife's slapstick chops, and her physicality continues to inspire the type of bits that they plan for her character.

"I'm very long," Olson explained to Buzzfeed. "I'm very unaware of how long my limbs are and I bash into things a lot, and Rob makes fun of me a lot ... I'll do something and Rob will tell me to do it again and I didn't even know it was funny."

Her costars, too, can attest to her lack of spatial awareness. "If there is a tack on the floor, she will step on it," added series co-creator Glenn Howerton, who plays Olson's onscreen brother Dennis.

Even though physical comedy can get dangerous, from harsh weather conditions to hard falls, "The Mick" star is too committed to her craft to ever consider substituting a body double. "I don't want the stunt double to do it, unless it's like a quick thing because that's part of the acting. I want to do that," she concluded. "There's a lot of acting that happens in between the running out and the head-hitting."

Although her safety is the top priority, Olson's risks have absolutely paid off by creating some of the funniest moments of the show in its several decades on air. If "Sunny" stays on the air for much longer, there may come a time when the actress is forced to call in a stunt double by the limitations of age. But until that day, we can expect to see Olson's limbs flying about for years to come.