West Ham midfielder Declan Rice has pledged his international future to England.
Rice, 20, has won three senior Republic of Ireland caps, all in friendlies, having played for his grandparents' country since under-16 level.
In August the Londoner said he needed time to decide his future, as winning a competitive cap for the Republic would have tied him to the country.
"This has been an extremely difficult decision," he said.
Rice, who has made 59 appearances for West Ham, has excelled this season in a defensive midfield role for the Hammers.
In a long statement on Twitter, he said: "I consider myself to be of mixed nationality. I have equal respect for both England and Ireland and therefore the national team I choose to represent is not a clear-cut, simple selection.
"Ultimately, it is a personal decision I have made with my heart and my head, based on what I believe is best for my future.
"I would also like to make it clear that, in requesting to transfer my national team representation, I am not taking for granted a call-up to the England squad."
Republic of Ireland manager Mick McCarthy said: "Declan rang me today and said he has decided to give it a go with England. Good luck to him."
Kevin Kilbane, who was born in Preston but won 110 Republic of Ireland caps, tweeted: "If you're a 'proud Englishman' then why play for us in the first place?"
England legend Gary Lineker tweeted: "He's one of our own....He's one of our own...Declan Rice....he's one of our own."
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Other players to change national team
In 2004, Fifa changed its rules so players could represent one country at youth level and then another at senior level - so long as they changed by the age of 21. In 2009 it was amended so players of any age could make a switch. Senior friendlies do not tie a player down to a country.
Since the rule changes, several players have taken advantage, including...
- Diego Costa, who played two friendlies for his native Brazil before switching to Spain, having lived and played in the country for several years
- Wilfried Zaha won two caps in friendlies for England before declaring for the Ivory Coast, the land of his birth. He now has eight caps for the African nation
- Thiago Motta played twice for Brazil in 2003 and started a career with Italy, the nation of his grandfather, in 2011
- Alex Bruce was eligible for the Republic of Ireland and Northern Ireland through his grandmother, playing for both countries in friendlies
- Nacer Chadli played once for Morocco before switching to Belgium, where he was born
- Two Russia players at the 2018 World Cup had previously played for the country of their birth, Roman Neustadter (Germany) and Mario Fernandes (Brazil)