Their secret is out.
Tony Henry belted out a version of the Croat anthem before the 80,000 crowd, but made a blunder at the end.
He should have sung 'Mila kuda si planina' (which roughly means 'You know my dear how we love your mountains').
But he instead sang 'Mila kura si planina' which can be interpreted as 'My dear, my penis is a mountain'.