The music industry has been left shaken this afternoon as it's been revealed that U2's longtime tour manager Dennis Sheehan has passed away.

Dennis, who was in his late 60s, was reportedly found unconscious in his hotel room at the Sunset Marquis Hotel in Los Angeles in the early hours of this morning, where he is believed to have suffered a cardiac arrest.

Paramedics were called but Dennis was found dead at the scene, according to TMZ. 

In an official statement on the U2 website today, Bono said, "We've lost a family member, we're still taking it in. He wasn't just a legend in the music business, he was a legend in our band. He is irreplaceable." 

Dennis' death occurred just hours after the lads played their first of five nights at The Forum in LA as part of their iNNOCENCE & eXPERIENCE World Tour.

During his incredible career, Dennis has also worked with the likes of Lulu, Patti Smith, Lou Reed, and Stone The Crows. Indeed, in 1972 he was on stage when the Stone The Crows guitarist, Leslie Harvey, was killed by an unearthed microphone.  

He later synced up with Peter Grant, manager of Led Zeppelin, and went on to assist him with many of Led Zeppelin’s biggest tours. 

In 1982 he began his long career with U2 after meeting their manager, Paul McGuinness. "The band works incredibly hard," he has said of the Dublin rockers. "With many bands, you get to a peak, and that’s it. With U2 they are still climbing that mountain."

Dennis' four decades in the entertainment industry were honoured by the Parnelli Awards Board of Directors with a coveted Lifetime Achievement Award at a glitzy ceremony in Las Vegas in October 2008.

When the accolade was announced, fellow tour manager Jake Berry commented on the unique closeness of Dennis and all four member of U2. "They’d do anything for him," he said.

"I think it’s his enthusiasm and love of the industry that has enabled him to maintain the breakneck speed that the job requires for all these years."

Our thoughts are with Dennis' family, colleagues and friends at this time.