Steve Bruce was today confirmed as Wigan's new manager and will take up his new role on Monday, a statement on the club's website said.
He has been ruled out of taking charge of the Latics for tomorrow's trip to Barclays Premier League leaders Arsenal due to a lack of time to prepare the squad.
As long ago as Monday, Wigan chairman Dave Whelan confirmed Bruce was to join the strugglers after opting to leave Birmingham.
But a hitch in his departure from St Andrews meant that it was not until this afternoon that he could be confirmed in his new role at the JJB Stadium.
The delay in Bruce's appointment was rumoured to be down to a £225,000 payment Blues claimed they were owed for image rights.
That was never confirmed by either party but whatever the problem was it has seemingly now been resolved, with Birmingham set to receive up to £3million in compensation from Wigan.
With Bruce ruled out for tomorrow's trip to the Emirates, caretaker manager Frank Barlow will take charge of the Latics as they look to end a run of seven straight defeats in the league - a streak which has seen them plummet to second bottom in the table.
Bruce, 46, replaces Chris Hutchings who paid for Wigan's slump with his job two and a half weeks ago.
Meanwhile sources close to Birmingham have played down speculation that Scotland manager Alex McLeish is to become Bruce's replacement at St Andrews.
Ladbrokes have closed the book on McLeish, who just failed to lead the Scots to the Euro 2008 finals after defeat in their final qualifying game against Italy.
But City insist it will be at least another week before a new manager is in place and Eric Black will operate in a caretaker role for tomorrow's Premier League game with Portsmouth.
Black, who played alongside McLeish at Aberdeen in the 1980s, has admitted to being 'flattered' at being linked with becoming Birmingham's new manager.
But he insisted: 'Although a lot of people have said a lot of nice things, many of which have been very flattering, I am trying to stay focused on Saturday's game with Portsmouth and then we will see how we go.'