Born in Edinburgh and educated at the Mary Erskine School there, Worrall was a member of the National Youth Music Theatre (1994). She studied history of Art at the University of Cambridge from 1995 to 1998 and at the London Academy of Music and Dramatic Art (LAMDA) in 2000.

In 2003 she played Irina in Michael Blakemore's Three Sisters with Kristin Scott Thomas and Kate Burton in the West End. She appeared as Sonya in John Byrne's Uncle Vanya with Brian Cox for the Royal Lyceum, and as Cinderella in Stephen Fry's original version for the Old Vic in London, for which she was listed as giving one of the five best stage performances of 2007, alongside Frances de la Tour, Kelly Reilly, Tamsin Greig and Kate Fleetwood. She has also acted in Peter Pan, The Lady from the Sea, Good, The Strange Undoing of Prudencia Hart, Gone With the Wind, Three Sisters, Twelfth Night, The Tempest, and has worked extensively with Director Lucy Bailey.

She also appeared as Melanie in Bunny and the Bull, premiered at the 2009 London Film Festival, and as a guest Artist in many British television series, including Midsomer Murders, Judge John Deed, Doctors, Ultimate Force, Heartbeat and Foyle's War, alongside David Tennant.

She appeared in the 2014 comedy film Paddington.