By Adam S. Levy - Breaking Celebrity News Staff Writer

Hugh Hefner called his ex fiancée Crystal Harris a liar late Tuesday, after the blonde beauty made some embarrassing claims about her sex life with the Playboy founder on the Howard Stern show earlier in the day -- including she only had sex with Hef once for "about 2 minutes," and didn't have an [expletive].

"Crystal lied about our relationship on Howard Stern but I don't know why," Hef tweeted Tuesday night, later taking it down. "Maybe a new boyfriend?"

"Crystal convinced me that she adored me. That was the first lie," he wrote to one of his followers. "