Ian Watkins, frontman of Welsh nu-metal band Lostprophets, has been jailed for 35 years for a string of child sex offences, including the attempted rape of a baby.
At his sentencing at Cardiff Crown Court, the judge said Watkins has "plumbed new depths of depravity".
As a rock star in his 20s, Watkins sold millions of albums and commanded arena crowds.
What his fans did not know was that he was, as a court has heard, "a determined and committed paedophile".
Det Ch Insp Peter Doyle from South Wales Police said: "There is no doubt in my mind that Ian Watkins exploited his celebrity status in order to abuse young children."
Ian Watkins was born in 1977 and grew up in Pontypridd, forming his first band, a thrash metal group called Aftermath, in his mid teens.
The rocker studied graphic design at university and started playing music as a drummer before taking the microphone when the singer of one of his bands quit.
Lozt Prophetz formed in 1997. Three years later, with the spelling of their name changed, they recorded their debut album, The Fake Sound of Progress, in a single week on a modest budget.
After the band were snapped up by Columbia Records and heavyweight manager Peter Mensch, whose company Q Prime looks after Metallica, Red Hot Chili Peppers and Muse, the album was re-recorded and re-released.
They soon started making waves in the US, where their second and third albums both reached the Top 40.
They reached their commercial peak in the UK when their third album, Liberation Transmission, went to number one in 2006.
They also had two Top 10 singles - Last Train Home in 2004, and Rooftops (A Liberation Broadcast) two years later.
Lostprophets were named best British band at the Kerrang! awards for two years in a row in 2006 and '07, although most critics afforded them little credibility.
Watkins, heavily tattooed, with piercings and a goth-influenced dress sense, led the group as they sold out arena shows and attracted huge festival crowds.
Peddling angst and rebellion, sweetened by anthemic choruses and a punk-meets-skater boy image, Lostprophets attracted many disenfranchised young fans.
Their last album, Weapons, came out in April 2012, eight months before Watkins was arrested.
We now know that while in the band, the disgraced star conspired with two female fans to abuse their babies as well as taking advantage of underage followers.
He has pleaded guilty to a series of "depraved" child sex offences, including the attempted rape of a baby.
In one case, he swapped messages with a woman in her 20s about her baby boy in which the frontman spoke of his desire to "make him mine" and to "cross the line".
Cardiff Crown Court was also given details of a 17-minute video in which the singer performed a sex act on the baby.
The video was filmed the day after the Weapons album was released and just hours after Watkins appeared on BBC Radio 1.
It emerged that he was a user of crack cocaine and crystal meth and he claimed to have no memory of the events in the video.
Prosecuting barrister Chris Clee said drugs played "a significant part in his offending against children". Watkins also planned to "teach" the babies how to take drugs, the hearing was told.
The singer used Skype to watch the other woman, aged 24, abuse her child. In the 45-minute video call, he talked to the mother about how they were going to use the baby for sex. Watkins referred to the woman and her baby as his "slave duo".
Police also found a box of camcorder tapes which showed Watkins in hotel rooms with young fans.
One 16-year-old girl from Boston, Massachusetts, contacted Watkins saying she was a fan and was a virgin and went on to meet him wearing a schoolgirl uniform in a New York hotel in October 2006.
Watkins was filmed taking part in sex acts and describing the girl as "my underage slut".
In October 2008, he filmed himself having sex with another 16-year-old Lostprophets fan.
Police are now appealing for other victims to come forward.
Watkins' ex-bandmates released a statement in October saying they had been "coming to terms with our heartache" since his arrest and that they would no longer make music as Lostprophets.
Watkins and the two mothers are due to be sentenced next month.