'Eastbound & Down' Star -- I'm a RAPPER Now!

He played an Oompa Loompa on the big screen ... and Kenny Powers' violent Mexican nemesis on TV ... but now, Deep Roy is cornering a new market ... STREET RAP!!!

The 55-year-old actor got straight up funky outside of Ocean Ave. Seafood in Santa Monica last night ... dropping some rhymes ... and even a few dance moves LIKE A BOSS!!

"Oh yeah ... uh huh ... Oh yeah ... uh huh."