Remember JUSTIN GUARINI . . . the guy who lost to KELLY CLARKSON on the first season of "American Idol"? Well, he's married with kids now . . . but he's claiming he was quite the playboy back in his "Idol" days.
At a recent performance of his one-man stage show, "Lovesick", Justin told the crowd that he and Kelly started hooking up while they were filming their HORRIBLE post-"Idol" movie, "From Justin to Kelly".
He didn't say how long they were together . . . but it was short-lived. He basically said he was left behind when Kelly's career started taking off, and his didn't.
But Kelly wasn't Justin's only conquest. Supposedly, he also had a "fling" with TAMYRA GRAY, who came in fourth that season.
Kelly hasn't responded . . . so it's unclear if she remembers who Justin is.