Christie Brinkley's ex-husband Peter Cook, 62, and fiancée Alba Jancou, 21, celebrated July 4 at a party in the Hamptons. Cook and Jancou were photographed together at a party hosted by skin-care CEO Peter Thomas Roth.The couple wore matching black and white outfits. Cook and Jancou got engaged two years ago in Greece. "We are very happy," Cook previously told People magazine.