Play the lead role (4)
I believe the answer is:
star
'play the lead role' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for star that I've seen before include "''Twinkle, twinkle, little ...'' (children's song)" , "Ball of fire" , "Possible Christmas tree topper?" , "Red Dwarf?" , "Famous person" .)