A lot of stars cheerful about Los Angeles Times (6)
I believe the answer is:
'a lot of stars' is the definition.
(I've seen this before)
'cheerful about los angeles times' is the wordplay.
'cheerful' becomes 'gay' (synonyms).
'about' is an insertion indicator.
'los angeles' becomes 'LA' (abbreviation).
'times' becomes 'x' (2 times 4 is 2 x 4).
'gay' going around 'lax' is 'GALAXY'.
(Other definitions for galaxy that I've seen before include "e.g. The Milky Way" , "Milky Way, for instance" , "host" , "Vast number of stars" , "Component of starry universe" .)