Some tentatively recalled musical (5)
I believe the answer is:
evita
'musical' is the definition.
(I've seen this before)
'some tentatively recalled' is the wordplay.
'some' indicates a hidden word (some of the parts of the word are used).
'recalled' says the letters should be written in reverse.
'ative' is hidden in the letters of 'tentatively'.
'ative' written backwards gives 'EVITA'.
(Other definitions for evita that I've seen before include "1978 Lloyd Webber musical" , "1996 musical film, starring Madonna" , "Andrew Lloyd Webber musical set in Argentina" , "Juan Peron's wife" , "Eva Peron" .)