The 29-year-old shot stopper joined on a four-year deal and provides some fierce competition in City’s goalkeeping ranks.
Ben Hamer spent three seasons at the Valley following an August 2011 move from Reading – the club with whom he began his career after signing as a 15-year-old.
Under the guidance of former City man Chris Powell, Hamer flourished for the Addicks, and was one of the standout performers for the Addicks in 2013/14, playing a key role in their survival.
Having represented the Club at Premier League and UEFA Champions League level, as well as enjoying a short loan spell with Bristol City, the 6ft 4ins goalkeeper is an imposing and commanding figure in the penalty area.
Despite never appearing for Reading in the league as a youngster, Hamer wasted no time in building an impressive reputation for himself out on loan.
That started with a 45-game spell at Crawley Town during 2006/07 – during which he was named Player of the Season for the then Conference outfit.
Four separate loan spells with Brentford followed for Hamer, of which the 2008/09 campaign was a standout one for the Taunton-born ‘keeper.
He helped the Bees storm to the League 2 title and kept a hugely impressive 20 clean sheets along the way.
Hamer missed just one match that season, and after another series of standout performances on loan at Exeter, then Charlton boss Powell swooped for his services in 2011.
The Addicks clinched the League 1 title in his first season, and the custodian proved to be a mainstay of the Charlton team ever since – making over 120 appearances in three seasons across all competitions.
Hamer, who is a fluent German speaker having lived in the country for part of his childhood, played twice against the Foxes in 2013/14, including Charlton’s 2-1 win at the Valley.
He made his league debut for City in the 1-0 victory at Stoke City in September 2014 – the Foxes’ first win of the 2014/15 Premier League campaign – before going on to make a further 16 appearances in all competitions over the course of the coming years.
Hamer spent time on loan at Bristol City in 2015/16, before appearing for the Foxes in the Champions League against FC Porto the following season.