Dan Nelson, a part-time singer and personal trainer from New York's Long Island, met Anthrax guitarist Rob Caggiano a few years ago and recently contacted him through MySpace, according to a statement issued Thursday by the band.
"It really is a dream come true," Nelson, 31, of Levittown, told Newsday.
Anthrax had a reunion tour with former singer Joey Belladonna in 2006, but talks fell through after that, according to the statement.
Nelson and the band met for a musical workout, and "right from the first second Dan started `Room for One More,' we knew," guitarist Scott Ian said in the statement, referring to a 1993 staple.
Anthrax was among heavy metal's biggest names in the 1980s and early 1990s, known for their speed, intensity and genre-crossing 1991 collaboration with Public Enemy on the rappers' "Bring the Noise."