Tottenham Hotspur have appointed Ange Postecoglou as their new manager on a four-year contract.
Postecoglou, 57, leaves Celtic after winning successive Scottish Premiership titles in his two seasons in charge.
He is Spurs' fourth permanent manager since Mauricio Pochettino led them to the Champions League final in 2018-19 and follows Jose Mourinho, Nuno Espirito Santo and Antonio Conte.
"We are excited to have Ange join us," said Tottenham chairman Daniel Levy.
"Ange brings a positive mentality and a fast, attacking style of play. He has a strong track record of developing players and an understanding of the importance of the link from the academy - everything that is important to our club," he added.
Spurs have been searching for a new manager since Conte's departure in March, with Cristian Stellini and Ryan Mason both taking charge on an interim basis.
Postecoglou - the first Australian to manage in the Premier League - arrives at Tottenham after winning a domestic treble in Scotland, where he has claimed five of the six trophies available to Celtic during his two campaigns with the club.
He is one of only five managers - along with Jock Stein, Martin O'Neill, Brendan Rodgers and Neil Lennon - to secure a domestic clean sweep with Celtic.
"It has been a pleasure working with Ange, a great football manager and a good man. He has served the club with such energy and determination and delivered a phenomenal level of success," Celtic chief executive Michael Nicholson said.
"Of course, we wanted Ange to stay at Celtic and while there is real disappointment we are losing him, he has decided he wants to look at a new challenge, which we respect."
New manager has no time to waste
Spurs have spent 10 weeks searching for Conte's successor, with Julian Nagelsmann, Luis Enrique, Brendan Rodgers, Arne Slot, Graham Potter, Julen Lopetegui and Pochettino all linked with the role at some point.
Since losing 2-0 against Liverpool in the 2019 Champions League final, they have claimed just one top-four finish in the subsequent four seasons.
Postecoglou is no stranger to arriving at a club facing a significant task having taken over Celtic in the summer of 2021 after they had finished the season 25 points behind champions Rangers.
When he arrived at Celtic, chief executive Peter Lawwell had been replaced by Dominic McKay, Nick Hammond stepped down as head of football operations and long-serving captain Scott Brown left to join Aberdeen.
There are several similarities as he walks through the door at Tottenham Hotspur Stadium, with chairman Levy searching for a new sporting director following the exit of Fabio Paratici, who resigned after losing his appeal against a 30-month ban from football.
Addressing the uncertainty surrounding the future of striker Harry Kane - with Real Madrid showing interest in the England captain - will be high on the agenda this summer as he looks to shape a squad capable of guiding Tottenham back into the Champions League.
From A-League to Premier League
Postecoglou's playing career was spent in Australia, primarily with South Melbourne, where he played under Ferenc Puskas and he attributes his coaching philosophy to the legendary Hungarian.
He stepped into management in 1996 with South Melbourne before winning back-to-back A-League titles with Brisbane Roar between 2009 and 2012.
After a season with Melbourne Victory he became manager of Australia in 2013 and guided his country to the 2014 World Cup as well as victory in the 2015 Asian Cup.
Further silverware followed during his time in Japan with Yokohama F Marinos, when he ended the club's 15-year wait for a J-League title in 2019.
Few in Scotland knew much about Postecoglou when Celtic appointing their new manager two years ago, but after initially struggling he delivered five trophies across two seasons.