Nigel Reo-Coker has passed a medical and completed a move to West Ham from Wimbledon.
Reo-Coker is an England Under-21 international
The 19-year-old had attracted interest from Crystal Palace, Leicester, Portsmouth, Tottenham and Cardiff this season.
But the England Under-21 international has agreed personal terms with the
"It is a big club and there is the opportunity to do well and get back in the Premiership," he said.
Reo-Coker is cup-tied for West Ham's fourth round FA Cup tie at Wolves but should make his debut in the Upton Park's next league game against Rotherham at home.
Reo-Coker added: "I am delighted to have signed and really looking forward to the chance of playing.
"There is a lot of potential at West Ham with the players and the manager we have here.
"I believe that West Ham can definitely get back into the Premiership first time, there are no doubts about it.
"We haven't lost many games though I know there have been a lot of draws - and I have every confidence things can move upwards."
Dons forward Adam Nowland is also expected to sign for West Ham after a fee was agreed for both players with the club's administrators.