West Ham are facing Sevilla tonight in the Europa League - but without their shirt sponsors Betway at the Ramón Sánchez Pizjuán Stadium in Spain.
Instead, the Premier League club lined up with an empty space on the front of their playing shirts where the Betway logo would normally have been.
That is because of gambling sponsorship laws in Spain, which prohibit football clubs from displaying betting companies and logos on their shirts.
This rule applies to visiting teams in European competition, in this case West Ham.
Similar rules are enforced in countries like France, who do not allow alcohol sponsorships on the front of playing shirts.
West Ham have reached the knockout stages of the Europa League for the first time and are facing an opponent in Sevilla who have won the competition on several occasions.
It comes as Chelsea’s shirt sponsor Three announced they had suspended their partnership with the club in the wake of the UK Government sanctioning Roman Abramovich.
Chelsea could line up against Norwich tonight in the Premier League without the Three logo - but this has nothing to do with West Ham playing without Betway in the Europa League.
