Charlie Day and His Wife Pretended to Be Siblings for an Audition and Shockingly Made Out

Charlie Day and Mary Elizabeth Ellis
Phillip Faraone/FilmMagic

Day also touched on working with Mary Elizabeth Ellis on 'It's Always Sunny in Philadelphia.'

Charlie Day and Mary Elizabeth Ellis know how to keep their marriage alive!

The couple and frequent co-stars have worked together on It's Always Sunny In Philadelphia, but also on Reno 911! While chatting with Kelly Clarkson on her Kelly Clarkson Show on Thursday, the I Want You Back star shared how he and his wife pretended to be siblings and awkwardly made out during the audition for the mockumentary-style comedy.

"We auditioned together for an episode of Reno 911! and they used to do improvised auditions. So Mary Elizabeth and I went into the audition and told them we were brother and sister and then we started making out in the audition," he hilariously recalled. "And they were like, 'Oh my god!…We have to cast them!'"

Clarkson looked shocked before laughing and adding, "That's amazing, oh my gosh. That could have gone either way. It was a gamble."

Day and Ellis have been married since 2006 and are parents to 10-year-old son Russell. The comedian and actor also touched on working together with his wife on Always Sunny and their character's love-hate relationship.

"I feel a certain amount of pressure if we're in the writers' room and no storylines have popped up for her character. I'm like, 'I can't go home and tell her this,'" he shared. "But it's also a blast, but she's very mean to me on the show."

"She really enjoys it. I think that's also healthy," he added.

Day and Jenny Slate, who also appeared on the daytime talk show, co-star in the rom-com I Want You Back. The story follows the two after they both get dumped and make a plan to try and get their exes back. Gina Rodriguez and Scott Eastwood also star.

I Want You Back streams on Prime Video on Feb. 11.