Actor, Dee's unusual ornament (8)
I believe the answer is:
decorate
'ornament' is the definition.
(I know that ornament can be written as decorate)
'actor dee's unusual' is the wordplay.
'unusual' indicates an anagram.
'actor'+'dee'='actordee'
'actordee' is an anagram of 'DECORATE'.
(Other definitions for decorate that I've seen before include "Award a medal to" , "Make more attractive" , "Improve the look of" , "'Adorn, beautify (8)'" , "Honour" .)