Manchester United assistant boss Carlos Queiroz has been appointed as the new coach of Portugal.
The 55-year-old, who had a previous spell in charge of Portugal in the 1990s, has signed a four-year contract to succeed Luiz Felipe Scolari.
"I'm very proud and honoured to go back to serve my country," said Queiroz.
His decision leaves United boss Sir Alex Ferguson without an assistant with just five weeks to go before the start of the new Premier League season.
Former United stars Mike Phelan and Brian McClair are already on the coaching staff at Old Trafford, as is Dutchman Rene Meulensteen, and they could take on extra responsibility in the short term.
Other candidates include Bordeaux coach Laurent Blanc, the former France defender who spent two seasons with United at the end of his career, and Benfica boss Pako Ayesteran.
It is with a very heavy heart that I leave the greatest football club in the world," Queiroz added.
"This has been a special period in my life both personally and professionally.
"To Sir Alex, I thank him for his faith in me and his knowledge, spirit and desire from which I will take strength and have confidence in my new role."
Although disappointed to see Queiroz leave the club, Ferguson was full of praise for his former assistant.
"Carlos is one of the best coaches in world football," Ferguson told United's official website.
"His attention to detail, ability to innovate and will to win have been a key factor to the team's recent successes.
"He has played an important role in building and blending the exceptional squad of players at the club."
The departure of Queiroz could also have implications for the ongoing transfer saga surrounding the unsettled Cristiano Ronaldo, with the two sharing a close relationship.
Ronaldo told Portuguese broadcaster RTP that he fully supported Portugal's decision to appoint Queiroz.
"He is a perfect choice. I have been working with him for some time and I just have to say that he is very good for this job," he said.
Queiroz's deal with Portugal's Football Federation (FPF) is believed to be worth around £1.5m.
FPF president Gilbert Madail said that Queiroz was his first choice for the post after Scolari departed for Chelsea at the end of Euro 2008 after five-and-a-half years in charge.
Queiroz has also previously managed Real Madrid, South Africa and the United Arab Emirates.
He has had two spells with United, first coming to Old Trafford in the summer of 2002.
He then spent an unsuccessful year in charge of Madrid before rejoining United on a one-year rolling contract in 2004.
The 55-year-old, who had a previous spell in charge of Portugal in the 1990s, has signed a four-year contract to succeed Luiz Felipe Scolari.
"I'm very proud and honoured to go back to serve my country," said Queiroz.
His decision leaves United boss Sir Alex Ferguson without an assistant with just five weeks to go before the start of the new Premier League season.
Former United stars Mike Phelan and Brian McClair are already on the coaching staff at Old Trafford, as is Dutchman Rene Meulensteen, and they could take on extra responsibility in the short term.
Other candidates include Bordeaux coach Laurent Blanc, the former France defender who spent two seasons with United at the end of his career, and Benfica boss Pako Ayesteran.
It is with a very heavy heart that I leave the greatest football club in the world," Queiroz added.
"This has been a special period in my life both personally and professionally.
"To Sir Alex, I thank him for his faith in me and his knowledge, spirit and desire from which I will take strength and have confidence in my new role."
Although disappointed to see Queiroz leave the club, Ferguson was full of praise for his former assistant.
"Carlos is one of the best coaches in world football," Ferguson told United's official website.
"His attention to detail, ability to innovate and will to win have been a key factor to the team's recent successes.
"He has played an important role in building and blending the exceptional squad of players at the club."
The departure of Queiroz could also have implications for the ongoing transfer saga surrounding the unsettled Cristiano Ronaldo, with the two sharing a close relationship.
Ronaldo told Portuguese broadcaster RTP that he fully supported Portugal's decision to appoint Queiroz.
"He is a perfect choice. I have been working with him for some time and I just have to say that he is very good for this job," he said.
Queiroz's deal with Portugal's Football Federation (FPF) is believed to be worth around £1.5m.
FPF president Gilbert Madail said that Queiroz was his first choice for the post after Scolari departed for Chelsea at the end of Euro 2008 after five-and-a-half years in charge.
Queiroz has also previously managed Real Madrid, South Africa and the United Arab Emirates.
He has had two spells with United, first coming to Old Trafford in the summer of 2002.
He then spent an unsuccessful year in charge of Madrid before rejoining United on a one-year rolling contract in 2004.