They play Francesca and Digby, the two charges of a young governess, Clara, played by the soon-to-be new Doctor Who companion Jenna Louise Coleman.
Ellie played Young Lily Evans in the final Harry Potter film.
Joseph Darcey-Alden (also A&J Management) is also a keen dancer and is currently appearing in Sadlers Wells production of The Snowman at The Peacock Theatre.
Christmas Eve 1892, and the falling snow is the stuff of fairy-tales.When the fairy-tale becomes a nightmare and a chilling menace threatens Earth, an unorthodox young governess, Clara, calls on the Doctor for help. But the Doctor is in mourning, reclusive and determined not to engage in the problems of the universe. As old friends return, will the Doctor really abandon humankind or will he fight to save the world – and Christmas – from the icy clutches of this mysterious menace?
Also guest-starring are Richard E. Grant, Tom Ward, and the hour-long episode is written by Steven Moffat. Doctor Who - The Snowmen will air in the UK on BBC One on Christmas Day at 5:15pm.