Aitor Karanka's protracted exit from Nottingham Forest was finally confirmed on Friday morning.
The 45-year-old Spaniard's future at the City Ground had seemingly been uncertain ever since Forest blew a 3-0 lead to draw 3-3 with Norwich on Boxing Day.
Karanka has now left his role as manager after asking to be released from his contract, a request the Championship club agreed to.
First-team coach Simon Ireland will take charge until a new manager is appointed.
A club statement read: "Aitor Karanka has asked to be released from his contract as the manager of Nottingham Forest Football Club.
"The club have agreed to this request and the terms of departure have been agreed. Both parties wish each other every success for the future.
"There will be no further comment from either party."
Karanka was appointed Forest in January 2018, and leaves with the Reds lying seventh in the Championship.
His final game in charge was Saturday's 2-0 FA Cup defeat by Chelsea, although Forest beat leaders Leeds a few days earlier to move to within four points of the top six.
Forest will now begin the search for a new boss, their 11th full-time manager since 2011.
Karanka previously guided Middlesbrough to promotion to the Premier League in 2016 but was sacked the following year.
Following his departure from Forest, Karanka said in a statement: "It's been an absolute privilege to manage this historic club.
"Thank you to Nottingham Forest, the staff at the stadium and the training ground, the players and the fans for all of your great support from the beginning to the end.
"I wish you all the best for the future. Come on you Reds!"