Hats (sometimes known in the American edition as Dating Service Video) was a game played on the British and American editions of Whose Line. The game involved all four performers, divided into two pairs. Each pair was given a box of "hats" (which often included masks and other articles of fancy dress) and had to come up with as many examples of a given thing - usually the "World's Worst Dating Service Video". The game was thus a combination of Props and World's Worst. One notable exception to this, however, was the "World's Worst Ad Campaign", a game which is generally undistinguished except for Greg's appearance as and impression of "Morocco" from the cartoon "Secret Squirrel". In keeping with his traditional antipathy toward Clive Anderson, Greg continued his pitch after the buzzer, giving the following monologue:
[buzzer] You put it on your face [buzzer] Then you buzz before it is funny [buzzer]
- In its first playing in the British version, Hats was introduced as a variety of World's Worst.
- In the American version, Hats is almost exclusively played when Greg Proops is present.