January Jones and Dominic Cooper stepped out for a dinner hosted by Donatella Versace at The Connaught in London last night. January rocked a daring backless dress as she mingled with the designer, Dominic, and British celebrities like Alexa Chung at the intimate event, which raised funds for Central St. Martins. The actress is in the midst of a hiatus from her TV series, Mad Men, but she'll soon kick off a new, film-heavy phase in her career. She costars in the upcoming X-Men: First Class, and her thriller Unknown hits the big screen in February.