Spain and Portugal have confirmed their commitment to putting forward a joint bid to host the 2030 World Cup.
The two countries announced in December they would investigate staging the global competition, ruling Morocco - previously said to be involved - out of a three-nation proposal.
Ahead of Wednesday's friendly between the sides in Lisbon, which finished in a goalless draw, the Spanish and Portuguese federations ratified an agreement to share the event.
"This agreement means an important step for this common project of federations, but also for the countries," RFEF president Luis Rubiales said in a statement.
"Soccer, sport, is a magnificent tool to inject strength and will to overcome in these moments of great difficulty.
"Few things can be more exciting than the opportunity to organise a World Cup and we cannot think of a better partner than Portugal. We go hand in hand with the Portuguese Federation."
Qatar are the next hosts of the tournament in 2022, while Canada, United States and Mexico are set to stage it four years later.
A decision on where the 2030 World Cup will be held is due to be made by FIFA in 2024, with the bidding process starting in 2022.
Morocco are also in the running, as are Uruguay, Argentina, Paraguay and Chile in a four-way bid.