Publicity video new duke supplied (8)
I believe the answer is:
provided
'supplied' is the definition.
('provide' can be a synonym of 'supply')
'publicity video new duke' is the wordplay.
'publicity' becomes 'pr' (abbreviation for public relations).
'new' indicates an anagram.
'duke' becomes 'd' (abbreviation).
'video' is an anagram of 'ovide'.
'pr'+'ovide'+'d'='PROVIDED'
(Other definitions for provided that I've seen before include "... on understanding that" , "Given" , "in the event" , "furnished" , "If - supplied" .)