Sailors after Sunday become celebrities (5)
I believe the answer is:
stars
'celebrities' is the definition.
(star can mean a famous person)
'sailors after sunday' is the wordplay.
'sailors' becomes 'tars' (tar is a kind of sailor).
'after' says to put letters next to each other.
'sunday' becomes 's'.
'tars' after 's' is 'STARS'.
'become' is the link.
(Other definitions for stars that I've seen before include "Horoscope (colloq.)" , "Celestial bodies of hot gases" , "Leading performers (with stripes?)" , "''What is the ...? What is the ...? '' (Juno and the Paycock)" , "Celebs - constellation" .)