O’Sullivan, one of the most successful Irish coaches of all time, previously worked for USA Rugby as an assistant and technical director in the late 1990s.

He returned to Ireland in 1999 and after rising to head coach in 2001, he led the team to three Triple Crown victories in the last four years.

He resigned in March 2008 after a disappointing RBS 6 Nations campaign.

“I am delighted to accept the invitation to coach the US Eagles,” O’Sullivan said. “It is an exciting challenge, which comes at a crucial period when I share their ambitions to qualify for Rugby World Cup 2011.”

“In re-joining USA Rugby I am going back to my coaching roots as it were and while I am delighted that much progress has been made since my last involvement, I am driven now by a determination that I share with the Eagles to demonstrate that USA Rugby has the resolve to establish its identity amongst the leading nations in the game.”

In his new role, he will be charged with continuing the development of the game in the United States, where it is popular at youth and college level but has little standing as a professional sport.

“We are obviously delighted to announce Eddie as the new Eagles coach,” USA Rugby chief executive Nigel Melville said.

“He is knowledgeable about the American game and has an outstanding track record as an international coach. Eddie has worked with the world’s top players and will bring enormous enthusiasm to the role.”