Gretel Scarlett Jahnke (/ˈdʒæŋkiː/), known as Gretel Scarlett (born 9 November 1987) is an Australian actress and performer. Having appeared in theatre productions including Wicked and Mamma Mia!, she is best known for starring as Sandy in the 2013–2015 Australian production of Grease and Kathy Selden in the 2016/2017 Australian production of Singin' in the Rain which opened at Her Majesty's Theatre, Melbourne. She most recently appeared in Disney's Frozen as the Elsa understudy.