Derry Girls star Nicola Coughlan is set to join Taskmaster.The show’s one-off New Year special, Taskmaster’s New Year Treat will feature five famous guests to take part in a number of challenges to win the Taskmaster trophy.Coughlan, who plays Clare Devlin in the Channel 4 comedy, will be facing off against actor John Hannah (Four Weddings and a Funeral) journalist Krishnan Guru-Murthy, presenter Rylan Clark-Neal, and Strictly Come Dancing judge Shirley Ballas.The celebrities will be set