Credit: Brian To/FilmMagic

Hugh Hefner has a reputation as a ladies' man -- and he's not about to let Crystal Harris ruin that.

Hours after his ex-fiancee, 25, told Howard Stern that sex with him lasted just "two seconds," the 85-year-old Playboy editor shared his side of the story on Twitter.

"Crystal lied about our relationship on Howard Stern, but I don't know why," Hefner wrote on Tuesday (the tweet has since been removed). "Maybe a new boyfriend?"

Hefner then told one of his followers that "Crystal convinced me that she adored me. That was the first lie."

"I feel sorry for Crystal," he told another follower. "She seems lost."

Harris, who dumped Hefner just five days before their June 18 wedding, was allowed to keep her $90,000, 3-carat diamond ring -- and her pricey Bentley! The only thing Hefner wanted in return? Custody of his dog, Charlie, who is now back at the Playboy Mansion.

Tell Us: Was Crystal wrong to dish on her sex life with Hef?