NEW COUPLE ALERT: KEVIN CONNOLLY & JULIANNE HOUGH

Les Deux featured a 1920s Flapper-themed party for Halloween, and we were shocked to see "Entourage" heartthrob KEVIN CONNOLLY (dressed as Gilligan) stroll into the shindig with 19-year-old "Dancing with the Stars" beauty JULIANNE HOUGH. The two made out most of the night. We know 33-year-old Kevin likes 'em young, but he can't go much younger than that without getting arrested!

Ex-girlfriend HAYLIE DUFF was there, too — and she was NOT happy!