Real had already qualified for the 32-team event in the United States by virtue of winning the 2022 Champions League.
Real Madrid will compete in the 2025 Club World Cup despite earlier Carlo Ancelotti comments indicating they could skip the Fifa event.
Carlo Ancelotti has claimed Real Madrid and other clubs will “refuse” to play at Fifa’s expanded Club World Cup.
O’Shea’s Ireland side face Ronaldo’s Portugal in a friendly.