TV icon Declan Donnelly is devastated following the death of his brother at the premature age of 55.
The Britain's Got Talent host raced to his brother's bedside, after he fell gravely ill, after collapsing.
The Catholic priest was said to be “extremely unwell” in hospital and his parishioners had been asked to pray for him.
The TV presenter, 46, wrote on Twitter: “I am heartbroken to tell you that my darling brother Fr Dermott, sadly passed away this afternoon. We are all beyond devastated. Thank you for your messages of sympathy and support, they are appreciated.”
Father Dermott was understood to have been a priest for 30 years.
In a statement a spokesman for Donnelly said: “It is with great sadness that we confirm the death of Fr Dermott Donnelly who died peacefully this afternoon in hospital surrounded by his family and close friends.
“We ask for the utmost privacy for the Donnelly family at this difficult time.”
Father Dermott Donnelly (left), the Catholic priest brother of ITV star Declan Donnelly has died Owen Humphreys
Messages wishing Father Dermott Donnelly, 55, were posted online as Catholic parishes in the north-east of England announced on Facebook that he had been admitted to hospital.
Father Donnelly died peacefully in hospital on Friday afternoon after a short illness Owen Humphreys
The news was confirmed by the Bishop of Hexham and Newcastle, who shared a statement shared by the Bishop said: "It is with great sadness that I inform you of the death of Fr Dermott Donnelly who died peacefully this afternoon in hospital.
"This has come as a great shock to all of us.
"Please pray for the repose of his soul and keep his family, especially his mother, in your prayers at this difficult time.
"Funeral arrangements will follow when finalised."
Father Donnelly began his career as a curate in Chester-le-Street until, two years later, he was asked by the Bishop of Hexham and Newcastle to found a youth programme aimed at introducing disadvantaged youngsters to the Catholic Church.
Revitalising the Youth Ministry Team into a thriving entity, he went on to launch the Global Youth Village Centre, on a former holiday camp in County Durham in 2010.
Over a 30 year period he continued raising money for the youth ministry, building the Emmaus Youth Village and developing youth leaders across the world.
In 2015, the Catholic Priest admitted his relation to Dec aided his efforts to bridge the generational divide between him and with parishioners.
He said: "I don’t advertise that I’m Dec’s brother, but the kids always seem to know. It bridges the gap between me and them."
He visited the outgoing Prime Minister Boris Johnson at No 10 in April this year, accompanying religious leaders including His Excellency the Papal Nuncio and His Eminence the Cardinal and members of the hierarchy of Ukrainian church in the UK, to pray for peace and unity in war-torn Ukraine.
In a statement he said: 'It was a real privilege to join Christian leaders from across many churches at Downing Street and to stand together in prayer, the silence was so profound.
"It was a moment when the power of vulnerability encountered the vulnerability of power. The best weapon we had was prayer."