First-look photos of Samantha Barks in full Frozen frocks while taping the Royal Variety Show have been unthawed. Perhaps best known for playing Éponine in the 2012 musical film adaptation of Les Misérables, Barks is set to originate the West End role of Elsa and is already turning heads with her brilliant and sparkly costume. Her run as the iconic Disney character is expected to begin at the Thea…