King has been training with Inverness and has done enough to earn a move to the SPL club. Caley boss Terry Butcher is pleased with the signing, and the 29-year-old will be available for the opening game of the season away to St Mirren on Saturday. "Simon has agreed to sign on Wednesday and that completes our first-team pool," Butcher told the club's official website. "He's a useful acquisition with good experience and we're pleased to land him." King made over 110 appearances for Gillingham after arriving from Barnet in 2007 and took in a loan spell with Plymouth Argyle last season.