Fat Elvis performed for party (8)
I believe the answer is:
festival
'party' is the definition.
(thesaurus)
'fat elvis performed' is the wordplay.
'performed' indicates an anagram.
'fat'+'elvis'='fatelvis'
'fatelvis' is an anagram of 'FESTIVAL'.
'for' acts as a link.
(Other definitions for festival that I've seen before include "Carnival or jamboree" , "Gala" , "Lift vase (anag.)" , "Holy day" , "Joyful celebration" .)