Mariann Gavelo

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…

Mariann Gavelo has a huge ass. We're talking Kim Kardashian style HUUUUUUUGEEE ... and it was all out on display at a party in Hollywood last night. Gavelo -- who appeared on "It's Always Sunny in Philadelphia" (the "Thunder Gun" episode) and in Will Ferrell's "Casa de Mi Padre" -- hit up the…