Brad Paisley and his wife, 'Nashville' star Kimberly Williams-Paisley, have been victimized in a bizarre scam involving a child who was allegedly battling neuroblastoma.

The incident started when Kimberly received an email from a woman who claimed that her daughter suffered from the pediatric cancer. “She said that her daughter had begged her to get in touch with me," the actress tells ‘Nightline.'

She didn't suspect that the email was anything other than genuine at first, with the mother even saying she had forgotten about her child's wish with everything else that was going on. "You know, that was kind of the beginning of the manipulation," Williams-Paisley states.

The pair communicated for the next 10 days via email, text messages and phone calls. The mother sent photographs that were allegedly of her daughter, whose name she claimed was Claire. She also sent journal entries and songs her daughter had sung for the actress, and Paisley even got on the phone to sing 'Amazing Grace.'

The Paisleys were devastated when they got a call saying the girl had passed away. "It's a parent's worst nightmare," Kimberly says.

"My wife started bawling," Brad adds soberly.

But the worst was yet to come. When the couple asked where they could send flowers, the mother did not want to give an address. That raised their suspicions, and eventually led to the discovery that the whole thing had been a hoax. The pictures of "Claire" had been lifted from the blog of another girl who really did suffer from neuroblastoma.

The news devastated Kimberly all over again.

"I vowed then I was going to find her," Brad says of the scam artist. "I'm going to find her, and I'm going to make sure this person isn't able to do this, or isn't capable of doing worse."

See the entire strange story unfold when 'Nightline' airs on Wednesday night (Nov. 6) on ABC.