Highlight of show's premiere: very French lead singer (6)
I believe the answer is:
stress
'highlight' is the definition.
(I know that highlight is a more specific form of the action stress)
'show's premiere very french lead singer' is the wordplay.
I cannot quite see how this works, but
'very' could be 'tres' ('very' in French) and 'tres' is found within the answer.
This may be the basis of the clue (or it may be nonsense).
'of' acts as a link.
Can you help me to learn more?
(Other definitions for stress that I've seen before include "nervous tension" , "possible cause of fracture?" , "what causes tension" , "Lay emphasis on - it's a strain" , "'Worry, pressure (6)'" .)