Ian Watkins, 35, of Pontypridd, appeared before Cardiff magistrates facing six charges relating to sexual offences against two young children.
He faces a charge of conspiracy to engage in sexual activity with a child under 13 and four offences relating to possession and distribution of indecent images of children.
He was remanded in custody.
The court heard that he had not admitted any of the offences, which date from May to December this year.
A 24-year-old woman has been charged with the same offences as Mr Watkins, while a 20-year-old woman is charged with five of the same offences but not conspiracy to rape.
Bail applications by all three were refused and they are due to appear before Cardiff Crown Court on 31 December.
Mick and Mairead Philpott, along with Paul Mosley, will face trial in February The parents of six children who died as a result of a house fire in Derby will now face manslaughter charges.