Siobhan Patricia Dillon (born 1 September 1984) is an English actress and singer, who rose to fame when she performed in the British talent show-themed television series How Do You Solve a Problem Like Maria? on BBC One in 2006. Since then, Dillon has performed in the West End, playing the roles of Sandy in Grease at the Piccadilly Theatre, Vivienne Kensington in Legally Blonde at the Savoy Theatre, Sally Bowles in Cabaret, Molly in Ghost the Musical at the Piccadilly Theatre, Ellen in Miss Saigon, and Betty Schaefer in Sunset Boulevard with the English National Opera. Siobhan reprised this role at the Palace Theatre in New York City.