Musical - girl is full of it (5)
I believe the answer is:
evita
'musical' is the definition.
(I've seen this before)
'girl is full of it' is the wordplay.
'girl' becomes 'eva' (**).
'is full of' indicates putting letters inside.
'eva' placed around 'it' is 'EVITA'.
(Other definitions for evita that I've seen before include "Andrew Lloyd Webber musical set in Argentina" , "Famous musical" , "Well-known musical" , "1978 Lloyd Webber musical" , "Stage musical" .)