Former Lostprophets singer Ian Watkins has died after being attacked in HMP Wakefield in Britain.
Watkins was serving a 29-year sentence for child sex offences.
Emergency services were sent to the prison in West Yorkshire but he was pronounced dead at the scene.
Watkins, 48, was jailed for 29 years in December 2013 with a further six years on licence, after admitting a string of sex offences, including the attempted rape of a baby.
He was arrested following the execution of a drugs warrant at his Pontypridd home on 21 September 2012, when a large number of computers, mobile phones and storage devices were seized.
Analysis of the equipment uncovered Watkins' behaviour.
A Prison Service spokesperson said: "We are aware of an incident at HMP Wakefield which took place this morning.
"We are unable to comment further while the police investigate."
A spokesperson for West Yorkshire Police said: "At 9.39am this morning, police were called by staff at HMP Wakefield reporting an assault on a prisoner.
"Emergency services attended and the man was pronounced dead at the scene a short time later.
"Detectives from the Homicide and Major Enquiry Team are investigating and inquiries remain ongoing at the scene."
