Mariann Gavelo's Ass Yes, It's Real ... And It's Not Done Growing!

5/18/2013 4:40 AM PDT

'It's Always Sunny' Actress Mariann Gavelo's Ass -- Yes, It's Real!


We already love Mariann Gavelo's redonkulous ass -- and now we love it even more -- because the smokin' hot actress tells TMZ her dumps like a truck are 100% real ... and getting bigger every day.

It was a moment for the history books ... Mariann displayed her booty at the Maxim Hot 100 party this week, but it was so spectacular ... an argument erupted in our newsroom: COULD IT BE REAL?

Mariann -- who's appeared in "It's Always Sunny in Philadelphia" and "Casa De Mi Padre" -- tells TMZ those cheeks aren't fake. She says, "My bottom is real ... Real!!!"

She explains, "I used large diapers as a kid. Seriously, the older I get, the bigger it gets." Hooray!

As for people (like us) who only comment on her curves, Mariann has a little message ..."Don't you like my face too?"

Um ... yes. yes. yes. yes. yes.