Bear Grylls is being praised for his role as the face of the evangelistic course Alpha last year as his period of service comes to an end.

The TV adventurer and explorer was the face of the 10-week course started by the charismatic evangelical church, Holy Trinity Brompton, in 2017.

Nicky Gumbel, vicar of HTB, thanked Grylls for allowing Alpha to use his story free of charge for the whole of last year.

'Bear is so generous granting these rights. He's helped many people explore faith in a positive empowering way,' he wrote on Twitter.

Alpha also posted on Twitter: 'On behalf of all of us at Alpha around the world we want to say a huge thank you to Bear Grylls for having allowed us (free of charge) to use his image and story as part of our global Alpha initiative in 2017.

'Bear has been so generous to us, granting us these rights for a year and we are so thankful. We want him to know he has helped so many people explore faith in a positive empowering way.'

Another Twitter user, Judith, added: 'He's helpful for so many situation in life! I've also been inspired by him to think of faith again and through him noticed Alpha.'

Grylls response by saying it had 'been a privilege to help you all in some small way'.

He agreed to help with promotion for Alpha after doing the course himself, saying it had had a profound impact on his life and personal faith.

'My Christian faith can be a little up and down, like any relationship' he said in a promotional video for the Alpha course. It has struggles, and it has doubts. But it has so often brought light to a dark path, warmth to a cold mountain and strength to a failing body.

'I remember crawling onto the summit of Everest and clearing the snow from my mask to see the curvature of the earth. But finding a simple faith that empowers my life – to me that has been my greatest adventure.'

Describing his Christianity to Stephen Fry, Grylls said: 'It has been the greatest strength of my life.'