Serve as comedian, performing around one (4,2)
I believe the answer is:
wait on
'serve' is the definition.
(I know that serve can be written as wait on)
'comedian performing around one' is the wordplay.
'comedian' becomes 'wit' (a witty person).
'performing' becomes 'on' (as in being on stage).
'around' indicates putting letters inside.
'one' becomes 'a' (a thing is one thing).
'wit'+'on'='witon'
'witon' placed around 'a' is 'WAIT ON'.
'as' is the link.
(Other definitions for wait on that I've seen before include "Be a servant to" , "Serve a meal to, or fetch and carry for" , "Hand food and drink to" , "Fetch and carry for a person, serve" , "Attend to, bring food to" .)