Film star rocks party, wearing nothing (6,4)
I believe the answer is:
'film star' is the definition.
(I've seen this before)
'rocks party wearing nothing' is the wordplay.
'rocks' becomes 'scree' (rocks on the slope of a mountain).
'party' becomes 'do' (do is a kind of party).
'wearing' means one lot of letters goes inside another.
'nothing' becomes 'nil' (eg nil is zero in football).
'do' inserted within 'nil' is 'nidol'.
(Another definition for screen idol that I've seen is " movie star".)