It was her first official public appearance since her contract malaria during the summer. Miss Cole, 27, was last night at the exclusive Nobu London to promote the Promise, a collaborative collection she launched the luxury jewelry business of Grisogono.Miss Cole has previously worn pieces of jewelry on The X Factor, and got an astonishing 250,000 for a 30-minute battle for the company to the Cannes festival in May. It was her first working day involvement in the nearly three months. She was joined at the event, as several of her celebrity friends, including Girls Aloud bandmates Kimberley Walsh and Nicola Roberts, X Factor judge Louis Walsh and interior designer Kelly Hoppen.