“The Masked Singer” fans got a jolt last night as the game show booted its first celebrity contestant — one who turned out to be a Denver Broncos football legend. Judge Ken Jeong guessed the costumed crooner as Hall of Famer John Elway, following guesses from other judges that included Tom Brady (from judge Jenny McCarthy), Billy Bob Thornton (from Rita Ora), and Troy Aikman (Robin Thicke).