Archbishop of Canterbury Justin Welby has released a film telling the story of how he came to understand the cross for the first time.

Marking Easter Sunday, the film, made for Thy Kingdom Come, a global, ecumenical prayer movement running from Pentecost to Ascension, sees the archbishop return to Cambridge where he became a Christian, together with the friend who led him to Christ.

Throughout the film Welby and his friend Nick Hills visit various places of importance on his journey of faith, including Hills' old room, where he gave his life to Christ.

The archbishop describes the night – on October 12, 1975, just before midnight – when the two friends returned to Hills' room after a church service. It was then that 19-year-old Welby made the decision which he describes as a 'transforming...life-changing moment'.

'I realise I was at the point of decision about my life. I realised my life was going to go one of two ways. And I prayed a very simple prayer saying, "Lord Jesus, come into my life. I don't know anything about you but come into my life." He came in and something changed. And has stayed changed from then on. With all the ups and downs and me trying to run away and good times in my life and really bad ones.'

In the same scene, the two friends thumb through the original Bible Hills gave to Welby. Viewers are shown a personal message with the scripture John 15:16, the same scripture that the Bible was open to when Welby was installed as the Archbishop of Canterbury five years ago (March 21, 2013).

He also reveals how he was prayed for by a family friend, every week from the moment he was conceived to age 18 when he became a Christian – something he found out much later.

'I later learned there was a particular person who prayed for me every week since he knew that I was on the way – since I was conceived, that I might become a disciple of Christ. I cannot tell you how grateful I am to them,' says.

He urges those watching to make the same commitment.

This message is at the heart of the Thy Kingdom Come campaign, which encourages Christians across the world to pray between Ascension and Pentecost for more people to come to know Christ.