Kentucky Derby Jockeys -- Tiny Sex Symbols

TMZ has learned 12 real life horse-racing jockeys -- 7 of whom are slated to ride in the Kentucky Derby -- shed their shirts for an upcoming "2012 Thoroughbred Racing Jockeys" calendar.

And get this: Mr. July is none other than 5'5", 108-pound stud Julien Leparoux (pictured left) ... who's slated to ride the odd-on favorite at the Derby ... Dialed In.

The mastermind behind the calendar -- Christine Sabia -- tells TMZ that Leparoux agreed to up the sex appeal by slathering on a layer of baby oil for the shoot ... you know, to give him that extra shine.