Assistant introduces film with Jeff Bridges for sponsor (6)
I believe the answer is:
patron
'for sponsor' is the definition.
(synonyms)
'assistant introduces film with jeff bridges' is the wordplay.
I cannot quite see how this works, but
'assistant' could be 'pa' (personal assistant) and 'pa' is present in the answer.
The remaining letters 'tron' 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 patron that I've seen before include "Pot ran out for protector" , "Sponsor or supporter as of the arts" , "Sponsor or benefactor" , "With help, he" , "manager (13) [FRENCH]" .)