Chesterfield have completed the signing of Angel Martinez on a two-year deal.
The 29-year-old spent last year with Millwall, but following their relegation to League One at the end of last season, he was among 18 players to be released.
However, he could now come up against the Lions, having agreed a switch to the Spireites.
"We've been waiting and waiting to sign him. He's got good pedigree having played at Espanyol and been capped by Spain at Under-21 level," manager Dean Saunders told the club's official website.
"He's good on the ball and he knows the central midfield position. With his experience of English football, I'm sure he'll make us better."
Prior to Millwall, the midfielder spent three years in England with Blackpool.
