Celebrity’s foremost lot on an islet, cavorting group of stars (13)

I believe the answer is:

constellation

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(Other definitions for constellation that I've seen before include "Star group" , "Draco, perhaps" , "Cassiopeia, for example" , "E.g Orion, Andromeda" , "Client to salon (anag.)" .)

I've seen this clue in The Independent.

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