John Potter has joined Sunderland as first team coach ahead of the players' return to pre-season training on Wednesday.
Potter has left his post as a coach at Scottish club Dunfermline to link up with Jack Ross and his assistant James Fowler, the 38-year-old is well known by Ross as they previously played together at St Mirren between 2008 and 2010.
Ross said: "I’m delighted to add John to the coaching team.
"He has terrific attributes as a coach and his personality and work ethic, allied to his past experience, will be of huge benefit in helping young players make the transition from Academy to first team."
Dunfermline chairman Ross McArthur said: “To the end, John acted with great honesty, integrity and respect, which is an example to others.
"Things have happened quickly this week, but Sunderland met our release terms, to allow John to make the move.
"On behalf of the Pars Family, I would like to wish John, Caroline and the boys well and I hope they have every success in the future."
Dunfermline manager - and former Sunderland winger - Allan Johnston added: "This was a great opportunity for Pottsie that was too good to turn down, as I myself know how big a club Sunderland are."
Meanwhile, Ross is hoping to add further signings to his Sunderland squad this week following the arrival of defender Alim Ozturk on a free transfer.
The Black Cats are in advanced talks with strikers Lyle Taylor and Chris Maguire and midfielder Dylan McGeouch, while a new goalkeeper is also a priority.
When Ross took charge of Sunderland he revealed he has never put too much focus on budgets during his managerial career. His Sunderland budget will evolve depending on the outgoings this summer and getting the high earners off the books.
In an interview with BBC Scotland, Ross said: "I've never been that bothered with budgets.
"I've seen my task in hand to try to get the best players I can with the resources and get the best out of them on the training pitch and put them together as a team.
"I don't even know my budget if I'm entirely honest. It will be something that will change and evolve depending on how the squad is trimmed.
"I know that I'm with a club that can compete healthily in that league and for a manager that gives you comfort as well."
Ross is targeting a quick return to the Championship after back-to-back relegations at the Stadium of Light.
He added: "I knew it was a big club, but now that I've been down for a month I didn't appreciate how big in terms of the stadium, support, training ground, everything.
"The club in terms of what it has at its disposal is huge.
"The owners are very good and they are very understanding of the huge raft of changes that are going on at the club and the challenges I will face because of that.
"They haven't stipulated that as a necessity, but I never shied away from my ambition with St Mirren and my ambition this season is to get promoted back to the Championship and start building and progressing from there."