Comedy club jester has bottom in ladies underwear (10)
I believe the answer is:
footlights
'comedy club jester' is the definition.
I can't tell whether this defines the answer.
'bottom in ladies underwear' is the wordplay.
'bottom' becomes 'foot' (foot is a kind of bottom).
'in ladies underwear' becomes 'lights' (I am not sure about this - if you are sure you should believe this answer much more).
'foot'+'lights'='FOOTLIGHTS'
'has' is the link.
Can you help me to learn more?
(Other definitions for footlights that I've seen before include "Theatrical profession" , "Theatre" , "Sources of illumination at front of stage" .)