A performer appearing in part is tense (7)
I believe the answer is:
artiste
'a performer' is the definition.
(artiste is a kind of performer)
'in part is tense' is the wordplay.
'in' indicates the answer is hidden within the clue.
'ARTISTE' is hidden in the letters of 'part is tense'.
'appearing' acts as a link.
(Other definitions for artiste that I've seen before include "A sitter for a performer" , "Attires (anag.)" , "'Public performer, dancer or singer (7)'" , "A sitter for creative person" , "Trouper" .)