Artist Paul reportedly drinks this well known brand (7)
I believe the answer is:
kleenex
'well known brand' is the definition.
The definition and answer can be both substances as well as being singular nouns.
Perhaps there's an association between them I don't understand?
'artist paul reportedly drinks' is the wordplay.
I cannot quite understand how this works, but
'artist' could be 'klee' (painter Paul Klee, 1879-1940) and 'klee' is present in the answer.
'reportedly' could be 'e' (I've seen this in other clues) and 'e' is located in the answer.
This may be the basis of the clue (or it may be nonsense).
'this' acts as a link.
Can you help me to learn more?
(Another definition for kleenex that I've seen is " Disposable tissue brand".)