Promotional material Britpop band put on book (5)
I believe the answer is:
blurb
'promotional material' is the definition.
(blurb is a kind of promotional material)
'britpop band put on book' is the wordplay.
'britpop band' becomes 'Blur' (band in Britpop genre).
'put on' means one lot of letters go next to another.
'book' becomes 'b' (abbreviation for book).
'blur'+'b'='BLURB'
(Other definitions for blurb that I've seen before include "Marketing text" , "giving brief description of it" , "Short printed promotional statement" , "Promotional statement on a book's dust jacket" , "Book endorsement" .)