Former Manchester United star Wayne Rooney been confirmed as Birmingham's new boss on a three-and-a-half year deal.
The former England skipper replaces the sacked John Eustace after leaving DC United last week.
"I am absolutely delighted to be joining Birmingham City at such an exciting time. It is very clear that they have a plan and are committed to realising their ambition for the club," said the ex-Manchester United striker.
"We are fully aligned on what is expected. I have been building my managerial career, putting myself in challenging environments, to get me ready for this opportunity. It's a project that gives me a sense of purpose and I can't wait to get started.
"We have some exciting young players in the squad, and some who are still to break through into the First Team, alongside a core of experienced senior professionals.
"I have a clear way that I want the team to play, and my coaching staff and I will work hard to implement it. We will create a winning culture here with an identity that gets Blues fans on their feet."
Former England team-mate Ashley Cole, currently England Under-21s assistant coach, and John O'Shea, the assistant coach of the Republic of Ireland, will join Rooney in Birmingham while keeping the roles with their national sides
Carl Robinson and Pete Shuttleworth, who both worked with Rooney at DC United, also move to St Andrew's.
US-based Shelby Companies Limited completed a takeover of Birmingham in July and owner Tom Wagner has been reportedly seeking to make a change of management, with Rooney's name linked with the club in September.
In August, seven-time Super Bowl champion Tom Brady became a minority owner in the club.
Eustace was sacked on Monday despite guiding Birmingham to sixth place in the Championship this season.
He replaced Lee Bowyer in July 2022 and helped Birmingham finish nine points above the drop zone in the second tier amid off-field issues surrounding the ownership of the club.
Birmingham co-owner and chairman Wagner said: "Wayne is a born winner. We believe, with the support of his coaching staff, the club, and our supporters, he will take Blues forward on the next stage of our journey.
"His playing philosophy will help to realise the ambitions we have set for Birmingham City.
"Wayne has been preparing for an opportunity like this since he embarked on his coaching education whilst still a player at Manchester United. He and his staff have the full support of the board and everyone at the football club."
Rooney was relegated with Derby in 2022, having battled a 21-point deduction for entering administration and breaching EFL accounting rules.
He quit soon after and joined DC United in July 2022, leaving last week after failing to reach the MLS play-offs.