Celebrity on mixed gins -- Leo, perhaps (4,4)
I believe the answer is:
star sign
'leo perhaps' is the definition.
(I've seen this before)
'celebrity on mixed gins' is the wordplay.
'celebrity' becomes 'star' (I've seen this before**).
'on' indicates putting letters inside.
'mixed' is an anagram indicator.
'gins' anagrammed gives 'sign'.
'star' placed into 'sign' is 'STAR SIGN'.
(Other definitions for star sign that I've seen before include "Eg, Sagittarius" , "Eg, Leo or Aries" , "Zodiacal figure" , "'Gemini or Scorpio, say (4,4)'" , "Cancer or Capricorn, say" .)