According to the announcement, Alexander-Arnold will be wearing the No.12 shirt, which is a designated number for all players in La Liga. This rule requires players to wear numbers between 1 and 25.

The No.12 shirt is a significant one in Real Madrid's history, as it was famously worn by Marcelo, a five-time Champions League winner. The number has also been worn by Eduardo Camavinga in recent times.

Real Madrid will be competing against Al-Hilal, Pachuca, and Red Bull Salzburg in the group stage of the tournament.

As a member of the team, Alexander-Arnold is expected to make a significant contribution to Real Madrid's performance in the tournament.

The FIFA Club World Cup is a prestigious international club football competition that brings together top teams from around the world.