Earl Sigma
From Tardis Wiki, the free Doctor Who reference
Earl Sigma is a blues player from Earth who plays blues songs in the city of Helen A realm. Earl Sigma helped him through the Kandy Man, snipers and loads of other dangers. After the Happiness patrol and Helen A were depossed Earl decided to stay on Terra Alpha and teach them the blues again. Earl's real name is not Earl Sigma, it is Earl, the natives call people from other planets Sigma's. (DW: The Happiness Patrol)