Aston Villa midfielder Jack Grealish's decision to play for England is a "bitter pill to swallow" for the Republic of Ireland, says former international Kevin Kilbane.
Grealish, 20, who represented the Republic at youth level, has chosen to play for the country of his birth.
"It was a difficult decision for him - he's been nurtured by the FAI at youth levels," Kilbane told BBC Radio 5 live.
"I'm disappointed because he would have been a great addition to the squad."
Birmingham-born Grealish turned down a place in the Republic squad in May.
Ex-midfielder Kilbane, who won 110 caps for the Republic between 1997 and 2011, added: "He decided himself that he wants to play for England and I respect him for it.
"He would probably have been the Ireland team now. Unfortunately it's not to be from Ireland's point of view.
"Hopefully for him he'll go on and have a successful career with England."
Born in Preston, Kilbane said he rejected the chance to play for England at youth level.
"I would rather have had one cap for Ireland than 100 for England," he said.
"I grew up wanting to play for Ireland. I knew from an early age - I'm very different from Jack in that respect."
Grealish, who made his first Villa appearance in May 2014, impressed last season and helped them reach their first FA Cup final for 15 years.