Brian Kidd has joined Portsmouth to assist caretaker manager Paul Hart following the sacking of Tony Adams.
The former Manchester United assistant boss will work alongside Hart while Pompey search for a new manager. The 59-year-old's position will then be re-assessed.
Hart told the club's website: "Brian's a fantastic coach with a great track record.
"We've known each other for an awfully long time and I'm delighted he's coming here to assist me."
Earlier today, Portsmouth executive chairman Peter Storrie admitted Adams was "very, very unlucky", but defended the decision to sack him after just 16 games in charge.
Pompey won just two of those games and are currently 16th in the Barclays Premier League, two points off the bottom of the table and one above the relegation zone.
Their next two games are at home to Manchester City and away to Stoke, and Storrie admits those fixtures played a major part in the decision to dismiss Adams.
"It was a very difficult decision, particularly when it's such a nice guy as Tony," Storrie told the club's website.
"I feel we have been very, very supportive of Tony but he's been a very, very unlucky manager.
"We've played well in games and not finished games off, there have been individual mistakes, but it was a point where we had to say, 'How many more games can we continue to be unlucky in?'.
"We have two vital matches coming up where we have to get points from and we felt we had to make the change now rather than later."
Despite their position, Storrie believes Portsmouth are well equipped to get out of trouble and secure their top-flight status.
"Tony said it and I think that's right, I'd much rather have the squad we have than six or seven other people down there fighting with us," Storrie added.
"We need to gel together, cut out the mistakes and just get going and get a couple of results. We must do everything we can to stay in the Premier League. It's a result business."