John Wetton, the bassist and singer for Asia, as well as a former member of King Crimson and U.K., has died at the age of 67 after a battle with cancer.

Wetton first came to rock fans' attention in 1972 when he joined a revamped King Crimson lineup, sticking with the group over a two-year span that included the records Larks' Tongues in Aspic, Starless and Bible Black and Red. Upon Crimson's temporary disbandment, he served stints with Roxy Music and Uriah Heep before co-founding U.K. with Yes vet Bill Bruford and embarking on a solo career.

All that early success, however, was just a warm-up for the multi-platinum frenzy that surrounded his next project. With A&R legend John Kalodner acting as musical matchmaker, Wetton joined up with former Yes members Geoff Downes and Steve Howe and ex-Emerson, Lake & Palmer drummer Carl Palmer to form Asia — a so-called prog supergroup whose self-titled debut topped the charts in the U.S. on its way to more than four million in sales.

Asia's quick start presaged a turbulent period for the original lineup, as they struggled to maintain their momentum, temporarily parted ways with Wetton, and ultimately disbanded following 1985's little-heard Astra LP. A late-'80s reunion ended with Wetton departing to resume his solo career, while Downes soldiered on with a new version of the group that persisted throughout the '90s and early aughts.

Wetton and Downes reignited their creative partnership after the turn of the century, coming together for a series of duo albums as Icon — activity that presaged the reunion of the original Asia lineup in 2006. After a successful tour, the group resumed recording, putting out a trio of LPs (2008's Phoenix, 2010's Omega and 2012's XXX) before Howe departed and was replaced by new guitarist Sam Coulson prior to the recording of 2014's Gravitas.

A number of health issues dogged Wetton during recent years, including a struggle with alcoholism that he openly acknowledged and a heart condition that required surgery and the postponement of a 2007 tour. More recently, Wetton went public with his cancer diagnosis, which forced him to pull out of Asia's scheduled tour dates with Journey so he could undergo chemotherapy.

"I accept the fact that I might not be here tomorrow, but having said that, having come through it you feel great," Wetton said after his heart surgery. "It gave me a completely new outlook on life, that it could all end tonight while I'm asleep, so let's make the most of today. Let's make the most of now."

"With the passing of my good friend and musical collaborator, John Wetton, the world loses yet another musical giant," wrote Asia drummer Carl Palmer in a statement. "John was a gentle person who created some of the most lasting melodies and lyrics in modern popular music. As a musician, he was both brave and innovative, with a voice that took the music of Asia to the top of the charts around the world. His ability to triumph over alcohol abuse made him an inspiration to many who have also fought that battle. For those of us who knew him and worked with him, his valiant struggle against cancer was a further inspiration. I will miss his talent, his sense of humor and his infectious smile. May you ride easy, my old friend."

"He will be remembered as one of the world’s finest musical talents, and I for one of many was wholly blessed by his influence," added Downes in a lengthy post. "It was a massive privilege for me to have worked with this genius so closely on our numerous projects together over the years. His bass playing was revolutionary. His voice was from the gods. His compositions — out of this world. His sense of melody and harmony — unreal. He was literally a 'special one.'"

In the short term, Wetton is scheduled to be replaced for the Journey tour by Yes vet Billy Sherwood; over the long term, Downes has signaled a determination to continue Asia in honor of his longtime partner. "It is the end of an era for all of us," he wrote. "But we will soldier on — the music of John Wetton needs to be heard loud and clear from the rooftops."