Gordon Strachan has returned to Celtic for a "three-month consultancy project" but will continue in his role as Dundee technical director.
Strachan will spend time looking at Celtic's activities within the academy, the women's team and the recently established B team, "with a view to providing recommendations" to club chief executive Dom McKay.
The 64-year-old, who managed Celtic between 2005 and 2009, said: "I am really looking forward to returning to the club to assist in these areas.
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"The development of young players and seeing them improve and grow is a real passion for me and I will do anything I can to support the club in these areas.
"Great people at Celtic always do great work. I look forward to building on this work, liaising with Dom and all our Celtic colleagues once again and hope we can work together for the benefit of the club and these teams so they ultimately can develop further and bring Celtic success.
"I also look forward to continuing my work at Dundee FC where I have established a great working relationship and close bond with the manager, managing director, staff and coaches."
McKay has been contemplating changes to the structure of Celtic's football department since taking over as chief executive earlier this year.
Nick Hammond left his role as head of football operations in March and has not been replaced.
On the former Scotland manager's appointment, McKay added: "Like all high-performance environments we never stand still and always seek development and improvement and I look forward to working with Gordon over the next three months, utilising the extensive expertise and knowledge he has to the benefit of the club.
"Gordon brings with him a wealth of experience in the areas of football development, from both his previous time here at Celtic and from the many roles he has held within football, including as our national team manager.
"Gordon achieved great things for Celtic as our manager. It goes without saying that he has a really close connection to Celtic and of course a tremendous affection for the club."
Dundee stressed that Strachan's short-term stint with Celtic would "not affect his role" at the Kilmac Stadium.
The Tayside club added: "Since taking the role in 2019, Gordon has been a fantastic asset throughout the club.
"His main role has been working closely with the academy coaches and helping to develop the future talents of the club, work which we are excited to see continue."