He plays up-and-coming talented gentleman detective (5,4)
I believe the answer is:
idris elba
'he plays' is the definition.
(Idris Elba is an actor)
'up-and-coming talented gentleman detective' is the wordplay.
'up-and-coming' shows that the letters should be reversed in order.
'talented' becomes 'able' (both can mean skilled).
'gentleman' becomes 'sir' (a man may be addressed as sir).
'detective' becomes 'di' (Detective Inspector abbreviation).
'able'+'sir'+'di'='ablesirdi'
'ablesirdi' back-to-front is 'IDRIS ELBA'.
(Another definition for idris elba that I've seen is " Actor".)