Famous actor, perhaps, one disembarking from flight (4)
I believe the answer is:
star
'famous actor' is the definition.
(I've seen this before)
'one disembarking from flight' is the wordplay.
'one' becomes 'i' (Roman numeral).
'disembarking from' suggests deleting specific letters.
'flight' becomes 'stair' (I've seen this before).
'stair' with 'i' taken out is 'STAR'.
'perhaps' acts as a link.
(Other definitions for star that I've seen before include "Big name" , "Top-of-the-bill artist" , "Main attraction" , "Asterisk" , "One guiding" .)