When P. Diddy spotted “King of Queens” tough cookie Leah Remini at a TinselTown bash, dogg started actin’ like his “Sean John” shorts were too tight or sump’n, man! Suddenly, His Diddy-ness was all OVER that girl — cuddling, holding hands — makin’ some HEAT, know what I mean? But P. and Leah kept trying to play cool, like they didn’t want anybody to catch on! They left separately — but minutes later were spy-balled secretly hooking up and carrying on at another party! What’s up with THAT? (Maybe Leah’s “new look” — low-cut dress and long straight hair a la J. Lo — got Diddy in a dither!)