Libby Phelps-Alvarez used to be a member of the notorious Westboro Baptist Church, hated across America for using slogans like "God Hates Fags" and picketing the funerals of dead soldiers.

She broke down in tears during an appearance on Anderson Cooper's "Anderson Live" show when a woman in the audience expressed the hurt she had experienced as a result of Westboro picketing her son's funeral.

Sharon Wyatt commended Phelps-Alvarez for being "brave enough" to leave Westboro.

"Our son died to ensure freedom of assembly, to ensure freedom of speech, to ensure freedoms for those that are white, black, gay, straight, rich, poor," she said.

Although Phelps-Alvarez had left the congregation by this time, Cooper pointed out that she had taken part in similar protests at the funerals of fallen soldiers.

Asked how she felt hearing Wyatt's pain, she said: "I just feel sad ... I'm sorry ... I just thought I was doing the right thing, but looking back now I see that I was hurting people."

Asked whether picketing was normal to her, she said, "Yes, it was very normal," adding that she started picketing at eight-years-old around once a week.

Asked why the church pickets service members' funerals, she explained: "The soldiers are fighting for a country that supports homosexuality and so they [Westboro] don't think they should do that and they are also picketing there to warn the family members and friends of the fallen soldier that they if they don't repent they are going to go to hell like that fallen soldier".

Her grandfather, Fred Phelps Sr, is founder of the fundamentalist church.

Explaining why she left, she said she got to the point where she "started questioning some things".

She said she knew leaving would mean she would never be able to talk to her family again, which she admitted feeling "sad" about because they were the only people she had been allowed to associate with growing up.

"I was pretty much leaving everything," she said.

Asked whether she ever felt bad while picketing, she said: "In the moment, I thought I was doing the right thing ... I thought I was loving my neighbour. I thought the only way to love my neighbour was to tell them their sins were taking them to hell. I honestly thought I was doing the right thing."