Double act reportedly producing such filth (6)
I believe the answer is:
doodoo
'such filth' is the definition.
I know nothing about this answer so I can't judge whether it can be defined by this definition.
'double act reportedly' is the wordplay.
'double' says to double the letters.
'act reportedly' becomes 'doo' (I can't justify this - if you can you should believe this answer much more).
'doo' duplicated is 'DOODOO'.
'producing' acts as a link.
Can you help me to learn more?
(Another definition for doodoo that I've seen is " filthy stuff".)