Bon Jovi's Alec John Such Asked for Help Before Death, Died of Natural Causes

Alec John Such, the original bassist for Bon Jovi, knew something was wrong in the hours leading up to his death, asking a friend for help in the middle of the night, TMZ has learned.

It was around 2:15 AM Saturday when Alec woke up at his South Carolina home to use the bathroom. On his way back to bed, Alec called out to a friend who was staying with him, the friend helped Alec get back into bed and then left the room, when the friend came back later to check on John, he was dead ... according to Tamara Willard, Chief Deputy Coroner for Horry County.

We're told EMS was called to the scene and performed life-saving measures but couldn't revive Alec. It's believed he died of natural causes ... no accident or foul play is suspected.

As we've reported, Jon Bon Jovi announced the tragic news Sunday ... saying he was heartbroken about Such's passing. As Jon noted, Alec was largely responsible for Bon Jovi coming together in the first place and introducing everyone from the very beginning.

Alec played with the band from 1983 through 1994, including their heyday. And, of course ... he contributed to many of their big hits. He ended up leaving BJ in the '90s, but rejoined them for their Rock and Roll Hall of Fame induction ceremony.