It seems when Nick Gruber is not hanging out, singing karaoke with teenagers, he's dating Hollywood animator John Luciano and talking to reporters at New York Post's "Page Six." Now the infamous boytoy says that 69-year-old ex-manfriend Calvin Klein has hired a private investigator to follow and intimidate him. "The investigator showed up at my table and started harassing me and my [boyfriend]. He said, 'Your boyfriend is in the mob and is being followed by the feds.' Then this morning he showed up at my hotel," Gruber told The Post's Tara Palmeri. "Calvin can hire goons to follow John and me all he wants -- we have nothing to hide. I've moved on. I've never been happier." Well, another source told "Page Six" that Klein hired detectives because the designer believes that, "Luciano and Gruber are involved in various unsavory business activities intended to embarrass him."