Emily Mortimer, who is in Disney’s big Christmas release, Mary Poppins Returns opposite Emily Blunt, Lin Manuel Miranda, Meryl Streep and Colin Firth, has signed with UTA. Most recently, Mortimer starred in Stacy Cochran's drama Write When You Get Work and Sally Potter's The Party and will next star in Isabelle Coixet's The Bookshop — which was released in Europe earlier this year, and for which she received a Goya Award nomination. On the television side, Mortimer…