Scholes has agreed to help his old club out for the remainder of the season.
With injuries biting deep into his squad, Sir Alex Ferguson made the dramatic move to ask his veteran midfielder to come out of retirement.
"It's fantastic that Paul has made this decision," said Ferguson.
"It's always sad to see great players end their careers, but especially so when they do it early.
"But he has kept himself in greatshape and I always felt that he had another season in him. It's terrific to have him back."