Star celebrated endlessly (3)
I believe the answer is:
sun
'star' is the definition.
(Sun is an example)
'celebrated endlessly' is the wordplay.
'celebrated' becomes 'sung' (as opposed to 'unsung').
'endlessly' means to remove the last letter.
'sung' with its last letter taken away is 'SUN'.
(Other definitions for sun that I've seen before include "Star; paper" , "Nice weather" , "Earth's nearest star" , "Hub of our planetary system" , "Centre of a solar system" .)