Convicted paedophile Ian Watkins is serving a 35-year jail sentence at Wakefield Prison for a number of sex offences including the attempted rape of a baby.
Watkins pleaded not guilty to possessing the device in his cell at the maximum security jail.
The 41-year-old appeared in court via a video link to face a charge of unauthorised possession of a mobile phone between March 4 and March 10, 2018.
The defendant, originally from Pontypridd in Wales, spoke to confirm his name and enter the not guilty plea during the brief hearing.
He wore denim jacket with a white collar for the hearing and his grey and black hair was tied back.
His trial, expected to last five days, has been listed for August 5.
Stephen Wood, prosecuting, said: “The jury will have to know about his previous convictions.”
Mr Wood added: “The issue here is that he was in possession of a mobile phone in his cell.
“I’m not going into specific details about what was found on that phone.”
Watkins was returned to custody after the hearing.
Watkins pleaded guilty at Cardiff Crown Court in 2013 to 13 child sex offences.
A judge said the case broke "new ground" and "plunged into new depths of depravity".
Watkins was sentenced to 29 years in prison with a further six years on licence, but he will be eligible for parole after serving two thirds of the prison term.
He was sentenced alongside two mothers, known as Woman A and Woman B, who also pleaded guilty to child abuse charges.
Watkins admitted the attempted rape and sexual assault of a child under 13 but pleaded not guilty to rape.
He also admitted conspiring to rape a child, three counts of sexual assault involving children, seven involving taking, making or possessing indecent images of children and one of possessing an extreme pornographic image involving a sex act on an animal.
Mr Justice Royce said Watkins had a “corrupting influence” and had shown a “complete lack of remorse”.
He added that Watkins posed a significant risk to the public, in particular women with young children.
After he was jailed it was revealed that South Yorkshire Police failed to act after Watkins' ex-girlfriend made allegations that he had sent her an indecent image.
The IPCC said South Yorkshire Police did not take seriously claims Watkins had been sharing indecent images.
IPCC commissioner Jan Williams said: "Having taken into consideration the nature and seriousness of the allegations against Watkins, the inaction of some South Yorkshire police officers involved may have placed a child at risk of further abuse for several months.