Jimi Jamison, the lead singer of US band Survivor, has died at the age of 63.
His booking manager Sally Irwin told TMZ that Jamison had died of a heart attack on Sunday night.
The band issued a statement on their Facebook page, saying they were "shocked and saddened" by Jamison's death. The band was due to embark on a new tour on September 12.
"The entire Survivor family is very shocked and saddened by the passing of our brother Jimi Jamison. Our thoughts, love and prayers go out to his family and friends," the statement read.
Jamison, who co-wrote and sang the on the Baywatch theme song I'm Always Here, joined Survivor after the disbanding of his own group, Cobra, in 1984.
He joined two years after Eye of the Tiger was released, and took over from the band's original singer Dave Bickler.
Jamison's first single with Survivor was The Moment of Truth, which became the theme tune for The Karate Kid, and the first album he appeared on with the band, Vital Signs, achieved multi-platinum status and included hit singles I can't hold back, High on You and The Search is Over.
In 1985, the band's track Burning Heart became the title track for Rocky IV.
After Survivor disbanded at the end of the '80s, Jamison worked on and released two albums, When Love Comes Down and Empires. It was during this period that he co-wrote the Baywatch theme tune.
Jamison rejoined the band in 2000, left again in 2006, and re-joined again in 2011. The last gig he played with Survivor was on Saturday.