See you at that party hosting stars (6-2)
I believe the answer is:
toodle-oo
'see you' is the definition.
(both can mean goodbye)
'at that party hosting stars' is the wordplay.
'at that' becomes 'too' (used for emphasis eg 'and a cheap one at that').
'party' becomes 'do' (do is a kind of party).
'hosting' is an insertion indicator.
'stars' becomes 'leo' (I've seen this before).
'do' going around 'leo' is 'dleoo'.
'too'+'dleoo'='TOODLE-OO'
(Other definitions for toodle-oo that I've seen before include "Goodbye (dated)" , "Farewell (old inf.)" , "Cheerio" , "Bye-bye!" , "Bye!" .)