The stepbrother of Elvis Presley wants to tell the world how important Christianity was to the King of Rock n' Roll. 

Billy Stanley goes into detail about the superstar's Christian faith in his new book, The Faith of Elvis, coming out in October. 

In an interview with the Observer newspaper about his famous stepbrother, Stanley said the music legend used to pray to God before every concert because it helped settle his nerves.

He remembered the two praying together at bedtime when he was a child and Elvis reading him Bible stories. 

He also recalls Elvis singing gospel songs at home. 

When it came to praying before shows, Stanley said that Elvis "always turned to God whenever he needed help".

"I asked him once, 'Why do you say the prayer before [each show]?' He said: 'It kind of settles my nerves but also I want God to help bless this concert, so make it a good one,'" Stanley said. 

Stanley said he wants to shed more light on Presley's Christian faith so that people can see past the "glitz and glamour". 

"Elvis was so appreciative of what the Lord had given him. He thanked God every day and constantly sought God's guidance through prayer and reading the Bible," he said. 

The 16 August will mark the 45th anniversary of Elvis' death. He died at Graceland on 16 August 1977 when he was 42.

Stanley's mother was Davada 'Dee' Stanley, the second wife of Elvis' dad, Vernon Presley.