Film actress in the dress circle (5)
I believe the answer is:
garbo
'film actress' is the definition.
(I've seen this before)
'the dress circle' is the wordplay.
'the dress' becomes 'garb' (synonyms).
'circle' becomes 'O' (O is a circle).
'garb'+'o'='GARBO'
'in' acts as a link.
(Other definitions for garbo that I've seen before include "film star? Yes and no" , "Old film actress" , "film-star" , "Female player once" , "Swedish-born actress" .)