Beau takes hat off to crazy cat who can ham it up (7)
I believe the answer is:
overact
'ham it up' is the definition.
(I've seen this before)
'beau takes hat off to crazy cat' is the wordplay.
I cannot quite understand how this works, but
an anagram of 'cat' is 'act' which is present in the answer.
The remaining letters 'over' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
'who can' acts as a link.
Can you help me to learn more?
(Other definitions for overact that I've seen before include "Be excessive on stage" , "Be unsubtle on stage" , "In part, fail to convince" , "Perform in an exaggerated manner" , "Play role exaggeratedly" .)