Chesterfield have signed MK Dons winger Jay O'Shea on an 18-month deal after his contract with the Dons was terminated by mutual consent.
The 24-year-old scored two goals in seven appearances during a successful loan spell at the Proact Stadium.
Boss Paul Cook told BBC Radio Sheffield: "He's a very talented boy who I think will score some special goals for us.
"The fans will be really pleased because he will only get better."
Cook added: "He is a great acquisition and is the kind of player that we want to bring to the club."
The Dublin-born player is likely to go straight into the squad for Saturday's match against Northampton.