Rob Gronkowski: I'm a Comedian Now ... On Showtime!

Ladies and gentlemen, give it up for the comedic stylings ... of Rob Gronkowski!

The New England Patriots tight end -- who's dabbled in comedy before -- is launching his own comedy special called, "Unsportsmanlike Comedy with Rob Gronkowski" ... which debuts Friday on Showtime.

Gronk will do some stand-up -- and host a handful of other comedians including John Caparulo and ex-SNL cast member Finesse Mitchell.

Looks like there will also be some chicks dressed as refs ... if refs wore striped bathing suits.

Gronk roasted David Ortiz last year in Boston ... so, he's got some experience.

Remember to tip your waitress.