Leicester boss Craig Levein has signed Alan Maybury and Mark de Vries from his former club Hearts for a nominal fee.
The loss of de Vries is a massive blow for Hearts
Defender Maybury, 26, and 29-year-old striker De Vries have signed three-and- a-half-year contracts with the Foxes.
The duo have been registered in time to play against Blackpool in the third round of the FA Cup on Saturday.
"We are not a short-term fix. The boss is trying to build something here as he did at Hearts and it is going to be good to be a part of it," Maybury said.
"The move all happened so fast but I am looking forward to it. I
know the coaches, Peter Houston and Kenny Black.
"It is important to play for people who have confidence in your ability and like your style of play."
Dutchman de Vries added: "Our aim is to bring success to Leicester and try to get them back into the Premiership."
"I am confident they will bring a lift to everyone connected with Leicester," he said.
The Foxes have had a difficult season back in the Championship after last season's relegation.
They were favourites to win automatic promotion but are currently 10 points off a play-off place.
Levein added: "We are at a stage of a season where we need to change things around a little and their arrival could not be better-timed."
Republic of Ireland full-back Maybury and Dutch forward De Vries could make their Foxes debuts in Saturday's FA Cup third-round tie with Blackpool.