Manchester United have named Walter Smith as assistant manager until the end of the season.
The former Everton and Glasgow Rangers boss fills the position vacated by Carlos Queiroz when he left last summer to take over at Real Madrid.
"The chance to come to Manchester United is something I couldn't turn down," said Smith.
"There are few bigger challenges in football than helping a successful side
sustain their achievements."
He added: "I have huge admiration for what Sir Alex has achieved at United and I'm excited to be part of it.
"I met Sir Alex in Glasgow on Tuesday. We were both attending a funeral. He asked if I'd like to give him and Mike Phelan a hand until the end of the season.
"When you're not doing a great deal and Manchester United ask you to come along then you're more than happy to do so."
United manager Sir Alex Ferguson said he welcomed Smith's arrival.
"There are few people in the game with his experience, knowledge and technical ability," said Ferguson.
"I am delighted that Walter has accepted the chance to join United.
"His talent and background will be major assets at such a critical time of
Smith, a former Dundee United and Dumbarton player, joined Rangers in 1986 and
became first team coach in 1991.
He won the Scottish Premier League title in each of the six seasons he was in
charge and picked up three Scottish Cups and three Scottish League Cups while in charge at Ibrox.
Awarded an OBE in 1997, he was appointed Everton manager in 1998 until he was dismissed by the club in March 2002.
Mike Phelan has been acting as assistant boss at Old Trafford since Queiroz's departure.