Christian singer and actor Pat Boone has asked for prayers for his wife of 65 years as she battles a life-threatening illness. 

Minister and friend Shawn Bolz told CBN that Shirley Boone is suffering from vasculitis, a condition that causes inflammation and clotting in the blood vessels. 

In a tweet on Wednesday, Boone said doctors had given up any hope of being able to heal Shirley of the condition. 

'My sweet wife of 65 years in serious illness at home..please pray for her, doctors have given up but doctor Jesus hasn't,' he said. 

Bolz told CBN earlier this month that Shirley had been sent home two months ago as there was nothing more they could do. 

'We are rallying prayer for Shirley who was sent home by doctors two months ago for possible hospice. She has lived an amazing life with Pat and her children, grandchildren, and friends but she has unfulfilled promise that she and all of us believe she has an opportunity to see,' he said. 

He added that she was taking anti-inflammatory medicine and that her vital organs were 'working 100%'. 

'She has a good chance and we are believing the push of prayer will help,' he added.

Boone at one time soared the music charts alongside Elvis Presley and starred in Journey to the Center of the Earth.

One of his last movie roles was in The Cross and the Switchblade in 1970, which tells the story of Nicky Cruz's conversion from New York gang leader to worldwide evangelist. 

He has focused his latter years on Christian ministry but still makes televised appearances from time to time, most recently appearing alongside the Jerusalem Symphony Orchestra at a gala to celebrate Israel's 70th anniversary.