The TV personality reportedly rushed to his brother's side, after the he was rushed to hospital, having fallen seriously ill. He was taken to hospital, after collapsing.
Father Dermott Donnelly was a Catholic priest who had taken Holy Orders in 1992. He took these orders at the same cathedral, where he subsequently officiated Dec's wedding to Ali Astall in 2015.
“I am heartbroken to tell you that my darling brother Fr Dermott, sadly passed away this afternoon", Dec tweeted. "We are all beyond devastated. Thank you for your messages of sympathy and support, they are appreciated".
"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", a spokesperson for Dec also added. "We ask for the utmost privacy for the Donnelly family at this difficult time".
Having started out as a curate in Chester-le-street, Father Dermott Donnelly was asked by the Bishop of Hexham and Newcastle to set up an outreach programme to introduce young people from disadvantaged areas to the Catholic Church.
"It is with great sadness that I inform you of the death of Fr Dermott Donnelly who died peacefully this afternoon in hospital", the Bishop said in a statement. "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".
