Crossword Genius

In which cast hears Lear, perhaps (9)

Ross

I believe the answer is:

rehearsal

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'in which cast' is the definition.
Although both the answer and definition are singular nouns, I can't see how one could define the other.

'hears lear perhaps' is the wordplay.
'perhaps' indicates anagramming the letters.
'hears'+'lear'='hearslear'
'hearslear' with letters rearranged gives 'REHEARSAL'.

Can you help me to learn more?

(Other definitions for rehearsal that I've seen before include "Practice - run-through" , "Play run-through" , "Practice session in preparation for public performance" , "Preparation for a show" , "Dummy run" .)

I've seen this clue in The Sunday Times.
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