Show thanks after I have turned up (5)
I believe the answer is:
evita
'show' is the definition.
(I've seen this before)
'thanks after i have turned up' is the wordplay.
'thanks' becomes 'ta' (UK informal version of 'thank you').
'after' is a charade indicator (letters next to each other).
'i have' becomes 'ive'.
'turned up' shows that the letters should be reversed in order.
'ive' reversed gives 'evi'.
'ta' after 'evi' is 'EVITA'.
(Other definitions for evita that I've seen before include "Stage musical" , "Juan Peron's wife" , "Show" , "Famous musical" , "Nineteen Dn musical" .)