Rangers have confirmed for the first time that Ally McCoist will take over as manager when Walter Smith steps down at the end of the season.
Assistant manager McCoist has been groomed as Smith's successor since the pair returned to Ibrox in January 2007.
The club have called a media conference for 4.15pm to formally announce the appointment.
The club revealed McCoist, who scored 355 goals in 581 appearances for the club, had agreed a one-year rolling contract with Kenny McDowall stepping up from the coaching team to become his assistant.
Rangers chief executive Martin Bain told the club's official website: "We are delighted to confirm Ally as our next manager when Walter Smith steps down at the end of the season.
"First and foremost Ally is a passionate Rangers supporter who has been a loyal servant to the club both as a player and more recently assistant manager. He has contributed greatly to our success over the past four years and that is why we feel he is the right man to replace Walter.
"When Ally joined Walter as his assistant in January 2007 he was always being groomed as the next manager. He is the unanimous choice of the Rangers board to take the club forward next season and when I offered him the position in December - - during our Champions League trip to Bursaspor - he agreed immediately.
"Walter Smith is rightly regarded as one of the most successful managers in our proud history and what he has achieved during the nine-in-a-row years and more recently in his second spell as manager is nothing short of remarkable.
"I am sure the supporters would join me in thanking him for his commitment and loyalty and I know he will work tirelessly to continue the club's success in the remaining months of the campaign."
McCoist said: "It was an honour to pull on the Rangers jersey during my playing career. I have enjoyed working with Walter, Kenny McDowall, Ian Durrant and the backroom team as assistant manager and to be confirmed as the next Rangers manager is a dream come true.
"Over the past few years I have been privileged to learn from one of the greatest managers in world football and Walter's record speaks for itself.
"The success he brought to Rangers during nine-in-a-row and the last four years in difficult times has been unbelievable and he has rightly gained the respect of everyone in the game.
"I am delighted to be following in his footsteps and I will do everything possible to bring further success to this club. I have said it many times - Rangers is a special club with a great history and tradition and this is the proudest day of my career.
"The fans have backed me for almost 20 years as a player and assistant manager and as a lifelong Rangers supporter myself I look forward to rewarding their loyalty by bringing silverware to our club."
Smith considered stepping down last summer after leading Rangers to a second successive Clydesdale Bank Premier League title.
But he stayed on to help the club through their financial troubles, which saw him unable to buy a player for almost two years.
McCoist's succession has been expected but never formally announced amid uncertainty over recent takeover interest.
Scottish tycoon Craig Whyte has been studying the club's accounts for several months with a view to making an offer.