Clio needs no introduction to director brought into play (4)
I believe the answer is:
used
'brought into play' is the definition.
(I've seen this before)
'clio needs no introduction to director' is the wordplay.
I cannot quite see how this works, but
'director' could be 'd' and 'd' is found in the answer.
The remaining letters 'use' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for used that I've seen before include "taken advantage of!" , "Second-hand, not new" , "Not fresh" , "Pre-owned" , "Second-hand; exploited" .)