Stage right, Oscar to play guitar (7)
I believe the answer is:
rostrum
'stage' is the definition.
(I've seen this before)
'right oscar to play guitar' is the wordplay.
'right' becomes 'r' (common abbreviation).
'oscar' becomes 'o' (phonetic alphabet: alpha, bravo, charlie etc.).
'to play guitar' becomes 'strum' (I've seen this before).
'r'+'o'+'strum'='ROSTRUM'
(Other definitions for rostrum that I've seen before include "stage" , "Conductor's dais" , "Podium" , "beak" , "Raised platform" .)