Film star seen in dress circle (5)
I believe the answer is:
garbo
'film star' is the definition.
(I know that Garbo was a film star)
'dress circle' is the wordplay.
'dress' becomes 'garb' (synonyms).
'circle' becomes 'O' (O is a circle).
'garb'+'o'='GARBO'
'seen in' is the link.
(Other definitions for garbo that I've seen before include "She sought solitude" , "film-star" , "Swedish film actress Greta" , "Swedish film star who wanted to be alone" , "Greta -, Swed. actress" .)