Admired player one in Dickensian musical (7)
I believe the answer is:
olivier
'admired player' is the definition.
(Lord Olivier, famous actor)
'one in dickensian musical' is the wordplay.
'one' becomes 'I' (Roman numeral).
'in' indicates putting letters inside.
'dickensian musical' becomes 'Oliver' (musical based on Oliver Twist).
'i' placed inside 'oliver' is 'OLIVIER'.
(Other definitions for olivier that I've seen before include "National Theatre's first artistic director, d. 1989" , "He starred in classic films of Hamlet and Henry V" , "Sir Laurence, once a great British actor" , "Great English actor playing rilievo" , "O! Virile (anag) - English actor, d. 1989" .)