Pan it dreadfully when he’s appearing in it as an actor (8)
I believe the answer is:
thespian
'an actor' is the definition.
('thespian' can be a synonym of 'actor')
'pan it dreadfully when he's appearing in it' is the wordplay.
I cannot quite understand how this works, but
'it' could be 't' (abbreviation. e.g. in 'tis) and 't' is present in the answer.
'when' could be 'e' (I've seen this in other clues) and 'e' is present in the answer.
'he' could be 'ian' and 'ian' is found in the answer.
This may be the basis of clue (or it may be nonsense).
'as' is the link.
Can you help me to learn more?
(Other definitions for thespian that I've seen before include "Relating to the theatre" , "Tragic actor" , "Dramatic performer" , "Actor - neat hips (anag)" , "Theatrical performer" .)