Series 4 saw the continuation of the themed live show format, in which the acts sing songs according to a different musical theme or genre each week. This format was introduced in series 3. Each week a celebrity guest connected to the theme performed in the results show, and some of the guests – Céline Dion, Boyz II Men, Girls Aloud and Michael Bublé – also coached the acts in rehearsal. Series 3 winner, Leona Lewis, appeared as a guest on the first live show on 20 October. During the results show she performed a premiere of her new single, "Bleeding Love", from her debut album, "Spirit". Series 2 winner, Shayne Ward, also appeared as a guest on the fourth live show. He performed his latest single, "Breathless", from his second album of the same name during the results show on 10 November. Westlife appeared on the sixth live show on 24 November singing "I'm Already There" from their 2007 album "Back Home". Duran Duran sang "Notorious" and "Nite-Runner" during the seventh live show results on 1 December.