Rachel Roy has been on vacation on St. Barts with Simon Cowell and his entourage of beauties on his mega-yacht. The New York-based designer has been spotted partying with Cowell and his coterie of women, including ex-fiancée Mezghan Hussainy and New York socialite Lauren Silverman. Despite furious speculation about which of the ladies Cowell may be romancing, we’re told it’s strictly platonic between him and Roy. Her rep told us, “She is on vacation with Simon. They are just friends.”