Famous clown having a hot drink (5)
I believe the answer is:
cocoa
'hot drink' is the definition.
(cocoa is a type of hot drink)
'famous clown having a' is the wordplay.
'famous clown' becomes 'coco' (Coco the Clown, 20th-century clown).
'having' says to put letters next to each other.
'coco'+'a'='COCOA'
(Other definitions for cocoa that I've seen before include "Warming bedtime drink" , "Chocolate powder" , "Kind of chocolate drink" , "brown powder" , "Main constituent of chocolate" .)