Mariann Gavelo - Damn is her Booty REAL? or FAKE? Good Lord

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.