Stone getting on and performing (7)
I believe the answer is:
staging
'performing' is the definition.
(performing on stage)
'stone getting on' is the wordplay.
'stone' becomes 'st' (abbreviation).
'getting on' becomes 'aging' (get on can mean to get older).
'st'+'aging'='STAGING'
'and' acts as a link.
(Other definitions for staging that I've seen before include "Putting on a show" , "Mounting (a play)" , "in the greenhouse" , "Putting on (a play)" .)