A comedy song about "teenie weenie beanies" is always going to be hit or miss, but the presence of Paul Rudd in the Tonight Show clip above manages to push it firmly into the "hit" category.
In the video, Rudd and Fallon team up to sing a very silly, Lonely Island-style song celebrating – you guessed it – tiny beanie hats.
Extra points have to be given for the sheer number of words they manage to rhyme with "beanie".
