Eg Hammerstein’s very large limousine (5)
I believe the answer is:
oscar
'eg hammerstein's' is the definition.
(lyricist Oscar Hammerstein)
'very large limousine' is the wordplay.
'very large' becomes 'os' (abbreviation for oversize).
'limousine' becomes 'car' (limousine is a type of car).
'os'+'car'='OSCAR'
(Other definitions for oscar that I've seen before include "Film prize" , "Film industry award" , "Develop again" , "Some players are given this" , "Mr Wilde - film award" .)