Rico Gedel, 25, was recorded on a prison officer's body camera making the remark after the depraved singer was killed in a brutal 20-second knife attack.
Rico Gedel, 25, allegedly killed Watkins, 48, in a 20-second jail cell attack before quipping, 'have a good night's sleep' as he lay dying, a jury heard.
Rico 'Rashid' Gedel, 25, is one of two men charged with murdering the disgraced rock singer, 48, at HMP Wakefield, West Yorkshire, in October last year.
Rico Gedel, 25, who previously appeared in court under the first name Rashid, was due to appear at Leeds Crown Court this morning along with Samuel Dodsworth, 43.
Rashid Gedel, 25, and Samuel Dodsworth, 43, are both charged with murder and will appear before Leeds Magistrates' Court this morning, West Yorkshire Police said.