Martin O'Neill's side take on the United States in an international friendly at the Aviva Stadium on Saturday evening and will do so with rainbow numbers on the back of their jerseys in place of the traditional white.
The FAI say that the move is to show support to the LGBT movement.
"Not just a number, this is a statement. Ireland, supporting LGBT rights," they posted on Twitter.
Meanwhile, for John O'Shea, the game will be the last of his 17-year international career and he already has one eye on a move into management.
The 37-year-old Sunderland defender will make his 118th and final appearance for his country but has already indicated he would like another season in club football when his current deal at the Stadium of Light expires at the end of the month.
O'Shea, who cut his teeth in professional football under the watchful eye of then Manchester United boss Sir Alex Ferguson, has revealed there have been no talks yet with the new regime on Wearside and - as he waits - developments, management and coaching are on the horizon.
He said: "It's something I've been preparing for for the last three or four years during the summer, taking my coaching licence with the FAI. But it's a long road and it's a sometimes treacherous road too, as I have learned the last few seasons.
"If I've learned from people that I've worked with throughout my career that I could give something back along those lines, I'd be foolish not to because I've been very lucky and fortunate to work with some amazing people."
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