Bit of fun with popular poet (6)
I believe the answer is:
larkin
'poet' is the definition.
(I've seen this before)
'bit of fun with popular' is the wordplay.
'bit of fun' becomes 'lark' (I've seen this before).
'with' is a charade indicator (letters next to each other).
'popular' becomes 'in'.
'lark'+'in'='LARKIN'
(Other definitions for larkin that I've seen before include "Orchestral violins, violas, cellos and basses" , "English poet, d. 1985" , "Scheme" , "See 15" , "Hull librarian and poet, d. 1985" .)