Ellen Terry's part to come on stage (5)
I believe the answer is:
enter
'come on stage' is the definition.
(synonyms)
'ellen terry's part' is the wordplay.
'part' indicates a hidden word.
'ENTER' is hidden within 'ellen terrys'.
'to' is the link.
(Other definitions for enter that I've seen before include "Gain admission" , "Enlist, join up" , "Enroll, sign up" , "Register formally as a participant" , "Inscribe" .)