Moore, 58, started out in Irish band Skid Row before being drafted into Thin Lizzy by frontman Phil Lynott to replace the outgoing Eric Bell.[break]
"I still can´t believe it," Bell told the BBC. "He was so robust, he wasn´t a rock casualty, he was a healthy guy.
"He was a superb player and a dedicated musician."
Belfast-born Moore started learning the guitar at eight and went on to forge a successful solo career between his two stints in Thin Lizzy, collaborating with George Harrison, the Beach Boys and Ozzy Osbourne.
Original Lizzy founding member Brian Downey paid tribute to his bandmate.
"I am in total shock," he said. "He will always be in my thoughts and prayers and I just can´t believe he is gone."
Thin Lizzy guitarist Scott Gorham added his own respects.
"Playing with Gary during the Black Rose era was a great experience, he was a great player and a great guy," he said. "I will miss him."
Moore received critical praise for his contribution to the 1974 Thin Lizzy album, Nightlife, and scored chart success in Britain with singles, Parisienne Walkways and Out In The Fields.
Legendary singer Lynott died in 1986 after battling alcohol and drug addiction.
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