Prepared to grab film star (6)
I believe the answer is:
bogart
'film star' is the definition.
(Humphrey Bogart 1889-1957)
'prepared to grab' is the wordplay.
'prepared' is an anagram indicator.
'to'+'grab'='tograb'
'tograb' is an anagram of 'BOGART'.
(Other definitions for bogart that I've seen before include "Humphrey --, US film actor" , "Lauren Bacall's first actor husband, d. 1957" , "See 12" , "American actor" , "Famous player" .)