US - Aspiring porn star Tiffany Hartford, 23, and her father George Sayers, 46, were arrested after a DNA test proved that they had a child together, said the police in Bethel, in the US state of Connecticut.
The two denied knowing that they were father and daughter, but Hartford allegedly introduced Sayers to a friend as her "husband/father", reported New York Daily News.
Hartford's mother claimed that she had tried to tell the authorities about the incestuous relationship more than five years ago, but was ignored.
Ms Vikki McConvey said she went to the police in 2007 after she suspected there was more to her daughter's relationship with Sayers than just father and daughter.
But she said the police told her that because Hartford was over 18 at the time, nothing could be done about it.
The pair were charged with third-degree sexual assault last Monday after DNA tests proved they are father and daughter and parents to their child.
Ms McConvey said she and Sayers had ended their relationship in1991. She moved back to Connecticut in 2006 so that her daughter could be near her father.