Kaitlin Olson Pregnant: 'It's Always Sunny' Couple Expecting Second Child

Kaitlin Olson and Rob McElhenney are expecting their second child. The funny couple have been married since 2008.

The couple, who star together in "It's Always Sunny in Philadelphia," wrote Olson's first pregnancy into the show with a plot line that involved the gang searching for the baby's daddy.

Here's a clip from "It's Always Sunny in Philadelphia."

Kaitlin Olson told People Magazine that she found out she was pregnant while celebrating her mother's birthday.

Olson said:

"We found out I was pregnant during my mom's birthday weekend in Ojai. I was instantly so proud of this baby for already knowing how to make someone else's special day all about him. We're having a boy! We're so happy that Axel gets to have a brother so close in age. And that I get to add another set of balls to my very, very male world."
The "It's Always Sunny" cast has celebrated a few other babies this year. Glenn Howerton and his wife Jill Latiano had a baby boy in September. David Hornsby and Emily Deschanel also had a boy in September, and Charlie Day and his wife Mary Elizabeth Ellis are expecting their first child this December.

Will family life ruin the crude humor of the "It's Always Sunny in Philadelphia" cast? Will Mac drop his funny fat?

Probably not. These guys will do just about anything for a laugh.