U2's travelling pastor, Rev. Jack Heaslip passed away in his home in Howth, Dublin after a long struggle with motor neuron disease.

The pastor spent many years on tour with the band, travelling with them and providing spiritual guidance to roughly 500 staff and crew members who were spending lengthy periods away from their family.

Described by Killing Bono author Neil McCormick, as a "gentle, thoughtful, soft-spoken, bearded man with strong spiritual leanings," Heaslip was not well known outside of the crew's circles but was well loved by everyone who knew him.

Patheos.com described him as the coolest man alive, while Rev. Val Rogers, the rector of Aughavale group of parishes where Rev Heaslip was also based, paid tribute to "his intelligence, courage and love."

"Pastor Jack is toasting with God in eternity now. We offer our sympathies and condolences, along with our love and prayers, to the Heaslip family and to the U2 community," the U2 blog posted.

"From the fans he never knew he had, those of us who have also felt his pastoral presence through concerts and albums, we agree with the liner notes from Songs Of Innocence and offer our thanks and fond farewells 'To Jack Heaslip, our North Star,'" it continued.

Heaslip first met the band members in the 70s when they were still in high school at Mount Temple Comprehensive School where he was guidance counsellor and chaplain. He eventually transitioned into an Anglican clergyman, ministering to a congregation of his own in west Mayo.

In 1983, he officiated the marriage of Bono and Ali, and continued his friendship with the superstars for the rest of his life.

In a rare occasion in 2001, he was recorded while he led the prayer before the start of the Elevation Tour in Miami during which he prayed that the people who attended the concert would be spiritually moved by the album, as well as all of the other music released by U2.

In 2014, his devotional entitled "A Tale of Two Mottoes," was included in the book Disquiet Time by Jennifer Grant.