08/07/2011 AT 04:00 PM EDT
He's the breakout star of Horrible Bosses
, fighting off Jennifer Aniston
's advances – and getting a little out of it during a certain vacuum scene.
Still, fans of FX's raunchy hit, It's Always Sunny in Philadelphia
, already know actor Charlie Day, 35, as the show's lovable (but oh-so-weird) Charlie, whose character has a penchant for killing rats in the basement of Paddy's Pub and dressing up in a neon green leotard as the unofficial mascot of the Philadelphia Phillies, Green Man.
But there's so much more to Day, and here's your chance to get to know the scene-stealer before It's Always Sunny
's season seven premiere arrives on Sept. 15.
1. He's Going to Be a Dad
On It's Always Sunny
, Charlie constantly chases after "The Waitress" (Mary Elizabeth Ellis), a still-unnamed server at a nearby coffee shop (and sometimes theme restaurant) whom he's obsessed with. The Waitress can't stand Charlie – going as far as to sleep with two of his friends – but in real life, Day has been married to Ellis since 2006 and the two are expecting their first child
2. He Once Played His Wife's Brother/Lover
When they were first dating, Day and Ellis played incestuous twins on a 2004 episode of Reno 911
. "Nothing says, 'This is the girl I want to marry' like pretending she's your sister and making out with her to get a job," Day has said. 3. He's Not Actually from Philadelphia
Day hails from Rhode Island – and he even lived in New York's Harlem neighborhood for awhile – and now resides in Los Angeles. Although he says he likes the City of Brotherly Love, there's one Philly staple he doesn't enjoy: "I don't care for cheesesteaks,"
he's said. "They make me s---- my pants."
4. He Made His Acting Debut Alongside Mary Tyler Moore
In 2000, Day made his first TV appearance, playing a mailroom clerk in the TV reunion movie, Mary and Rhoda
, starring Moore and Valerie Harper.
5. He's a Musicologist
Both of his parents are music teachers, and Day's written a lot of the music featured on It's Always Sunny
– "The Nightman Cometh," anyone? – but in real life he's a classical music fan. Debussy is a favorite, and Day admits to trying to learn "Clair de Lune"
on piano through YouTube instructional videos. "I think I got to a certain age where I decided I’d rather be a baseball player than a musician," he says of giving up on piano lessons as a child. "Now, like most kids, I regret it."