Speaking to The Daily Telegraph, he explained what his faith was like growing up: "Everything was liturgical and in cassocks and Latin and 'You're in trouble because you're late'. It was distant and cold and gave a false impression that God is distant and cold.
"And for me, it has been a lifetimes' journey that is still continuing of unravelling religion from faith. The heart of Christ's message was about freedom and fun and light and love and forgiveness and risk-taking - always messy. But my experience as a child was of it being too neat".
He also described his friendship with HTB (Holy Trinity Brompton) leader Nicky Gumbel, who started the evangelistic course alpha, of which Bear Grylls is now an ambassador.
"I do go to HTB a few times during the year, but mainly to have lunch with Nicky before or after. I don't feel I have ever been a fully fledged member of any church. Having said that, I have observed his church from the sidelines for 20 years and I think he runs an outward-facing, lovely church, full of love and acceptance."
"Nicky's leadership is rooted in humility. You see some church leaders and it becomes all about them, and their wealth their buildings, if you're this or that. Nicky has never been like that."
The adventurer was talking about his new devotional book, which it was announced he was writing last year, being published by Hodder Faith, who also publish authors like Tim Keller, Pete Greig and Krish Kandiah.
It is his first faith-based publication and speaking about the book, Soul Fuel, he explained that it was originally written for his three sons but based on his exchanges with his friend Jim Hawkins: "With Jim, I've done a daily thing for many years - reading the Bible together and then emailing thoughts and some feeling and some struggles. Just short, 10 minutes."
However, he added that he is hesitant to be public about his faith, saying "half of me is a bit self-conscious, and a little bit apprehensive.
"Faith is a really intimate subject. And a difficult subject.
"I could have not done a book on faith and it would be a lot safer."
Bear Grylls was also a contributor to Justin Welby's book In This Light: Thoughts for Christmas, a collection of musings by the Archbishop of Canterbury from people across public life about their faith and stories.
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