The Rev. Moises Cotto led the Congregation of Yahweh Templo El Candelero in Newark. Prosecutors say he began an affair with congregant Brenda Pabon in 2008 and that the couple would meet at a motel in Linden.
They were accused of forcing the girls to tape their sex acts until one of them told a parent this May.
Cotto pleaded guilty Thursday to two counts of endangering the welfare of a minor.
The 55-year-old East Orange resident, who has been held on $1.3 million bail since his arrest, is to be sentenced in January.
The 37-year-old Pabon is being held on $750,000 bail.