Surprised Oscar, about to get into bed (10)
I believe the answer is:
bewildered
'surprised' is the definition.
(I've seen this before)
'oscar about to get into bed' is the wordplay.
'oscar' becomes 'wilde'.
'about' becomes 're' (regarding**).
'to get into' means one lot of letters goes inside another.
'wilde'+'re'='wildere'
'wildere' inserted within 'bed' is 'BEWILDERED'.
(Other definitions for bewildered that I've seen before include "Perplexed" , "Surprised" , "Baffled" , "appearing clueless" , "At a loss!" .)