Adventurer Bear Grylls has said that his faith in Christ is now stronger than his fear of what others might think.

He admits Christianity is a crutch but adds that it is also "so much more than that".

Grylls is among the prominent evangelical Christians who feature in the new Alpha film series to go with the phenomenally successful Alpha programme for people new to church and Christianity. More than 29 million people have now tried Alpha at a local church or venue, in 169 countries.The 16 new short documentary style films are being offered to churches as an alternative to the traditional Alpha talks.

Grylls, filmed swimming and lighting a fire in a jungle on the ocean, said: "For so many years I always just strived to be strong in myself. It was as if all I needed was me and my buddies and we'd be, like, invincible.

"But the truth is none of us are. And I don't want to do this thing called life, I don't want to do it on my own. It kind of feels as if my longing for this light inside is now stronger than my fear of what others might think.

"People ask, doesn't that make faith like a crutch? Maybe. What does a crutch do? A crutch helps you stand, makes you stronger. In that case, sure, I need that. But especially when it's so much more than that."

He added: "This faith inside is also like a backbone, helping me stand tall and helping me be strong when I'm really up against it, facing those odds, whether it is on a mountain or stuck in some jungle, or just dealing with the storms of life. Sure I need that. But at heart my Christian faith says I'm known, I'm known to Christ."

The series, filmed in locations across the world, also stars Jackie Pullinger, one of the world's best-known missionaries, based in Hong Kong, Cardinal Christoph Schönborn, Archbishop of Vienna, Father Raniero Cantalamessa, Preacher to the Papal Household, Jose Henriquez Gonzalez, one of the 33 miners trapped for 69 days at the San Jose mine in Chile and Alister McGrath, professor of science and religion at the University of Oxford.

The first film opens with Alpha pioneer Nicky Gumbel talking about questions from basic ones such as "What shall I wear?" to bigger "life" questions such as "Why am I here?" and "Where am I heading?"

Gumbel confesses that in his early life he was not at all interested in Christianity. He was not brought up in the church and neither of his parents were Christian.

"First of all, I just thought it was so boring. Everything to me about church, Christianity and religion was just dull and it kind of made me feel a little bit guilty. I didn't know why."

He added: "I also thought it was untrue." He said he described himself as a "logical determinist" and enjoyed arguing with Christians. "I couldn't see how someone who lived 2,000 miles away, 2,000 years ago, had any relevance to my life today."

He started thinking there had to be more to life and was converted as a young man. 

Presenter Gemma Hunt explains that Alpha is designed for people who are not Christians or regular churchgoers.

Rev Tim Hunt, a Church of England clergyman, says: "Ultimately there's only one relationship that is totally loving and goes on forever and that is with God." He said Jesus was the way to that relationship and that Jesus is "the lens through which we see God". 

A vox-pop for the series, where passers-by are asked where they go for answers to the big life questions, elicits the commons response: "Google". One young man says: "Google or my grandmother."