The host chats to music superstar Mariah Carey about her eponymous Magical Christmas Special. TV chef and writer Nadiya Hussain reflects on new book Nadiya Bakes, while British astronaut Tim Peake talks about his autobiography Limitless. Pointless co-presenter Richard Osman discusses his debut crime novel The Thursday Murder Club. Singer-songwriter Gary Barlow also enjoys a brief natter before he performs the single Incredible, from his new solo album Music Played by Humans