Artist, one overdoing it, placed on stretcher (7)
I believe the answer is:
rackham
'artist' is the definition.
(illustrator Arthur Rackham)
'one overdoing it placed on stretcher' is the wordplay.
'one overdoing it' becomes 'ham' (ham can mean an actor who overacts).
'placed on' says to put letters next to each other.
'stretcher' becomes 'rack' (I've seen this in other clues).
'ham' after 'rack' is 'RACKHAM'.
(Other definitions for rackham that I've seen before include "4 ---, fairy-tale illustrator" , "Arthur ---, English illustrator" , "Arthur -, noted C-nineteen-twenty illustrator" .)