Joshua Harris has opened up about his changing beliefs in his first interview since his shock announcement that he no longer considers himself a Christian. 

The I Kissed Dating Goodbye author told Axios on HBO that he had excommunicated people in the past when he felt that their lives were not lining up with the Bible.

Eventually, he decided that this standard should apply to himself. 

"I was a leader and a spokesman and I called people to live in very particular ways, to sacrifice in very particular ways. And so for me to change in my thinking feels like a betrayal to them," he said.

"I excommunicated people. If you're not living according to the teaching of the Bible and you're living in unrepentant sin, then you have to be put out of the church.

"And I think I came to a point of recognising, 'You know what? I'm not living according to this. And I held other people to this standard.' And, you know, I excommunicated myself essentially."

I Kissed Dating Goodbye was one of the definitive books on Christian dating and relationships in the nineties, becoming a bestseller that was widely read in young Church circles. 

Harris went on to become lead pastor of the Covenant Life Church, part of Sovereign Grace Ministries in Gaithersburg, Maryland.

In 2016, he apologized for some of his ideas in I Kissed Dating Goodbye and said he was sorry to anyone who had been "misdirected or unhelpfully influenced" by the book.

But the real bombshell came earlier this year when Harris first announced that he and his wife were separating, before revealing a few days later that he was no longer a Christian. 

In the HBO interview, he said his marriage ending was a factor in his decision to "excommunicate" himself. 

"I was really just trying to be honest about the fact that all the ways that I had defined faith and Christianity that I was no longer choosing to live according to those — most significantly, the decision that my wife and I made to end our marriage," he said.