Manny Pacquiao -- CELEB TRAIN KEEPS ROLLIN' ... Works Out W/ Mickey Rourke

Another day, another star at Manny Pacquiao's (pack ee owz) L.A. training camp -- TMZ says Mickey Rourke swung by for a workout. Rourke showed up wearing a camouflage vest and some tight white bike shorts when he arrived at Wild Card Boxing Club in Hollywood ... while Manny was inside traing for is upcoming fight with Floyd Mayweather Junior on May 2..
PacMan has been working out with a BUNCH of big stars lately -- including Tim Tebow, Dave Chappelle and Cuba Gooding Jr. Muhammad Ali is also rooting for him.
Not a bad fan base.