Celebrity, showing no interest, we hear? That's right (9)
I believe the answer is:
starboard
'right' is the definition.
(right side of a ship)
'celebrity showing no interest we hear?' is the wordplay.
'celebrity' becomes 'star' (I've seen this before).
'showing no interest' becomes 'bored'.
'we hear?' shows a homophone (sound like).
'bored' is a homophone of 'board'.
'star'+'board'='STARBOARD'
'that's' is the link.
(Other definitions for starboard that I've seen before include "Right side of ship or plane" , "Right-hand side of ship while facing forward" , "Ship's right side" , "Literally, the steering side of a vessel" , "One side of a ship" .)