One gallery featured in film (7)
I believe the answer is:
acetate
'film' is the definition.
(type of material)
'one gallery' is the wordplay.
'one' becomes 'ace' (ace has a value of one in some card games).
'gallery' becomes 'tate' (Tate Modern, Tate Britain etc).
'ace'+'tate'='ACETATE'
'featured in' is the link.
(Other definitions for acetate that I've seen before include "Transparent film" , "film on overhead projector" , "Transparency; textile fibre" , "Textile fibre, plastic" , "Demo disc" .)