Fans of Real Madrid may have noticed a difference in the jerseys of the players during the match against Juventus. Many noted the odd design of the player numbers on the back of the shirts. Far from the black lettering that corresponds to Real Madrid’s third kit, the one used against Juventus was a colorful alternative.

The answer is that the Real Madrid jersey worn during the game is a collector's edition that was made specifically for the Juventus match in support of the club's partnership with Common Goal, the charitable organization founded by former Manchester United midfielder Juan Mata. Common Goal asks active players to donate 1% of their salaries to a fund that supports football charities all over the world. Juventus also changed their jersey numbers for the event, and one of the game-used shirts from each club will be auctioned off to raise money for the cause.