The 27-year-old, who was a late addition to Vicente del Bosque's squad after David Villa withdrew through injury, says it is a "dream" to be selected to represent la Roja
The 27-year-old was a late addition to Del Bosque's squad for the World Cup qualifying matches against Belarus and Georgia after Villa was withdrawn from Atletico Madrid's 2-1 win over Celta Vigo with an ankle injury.
Spain are 5/1 with BetVictor to beat Belarus 3-0
"I want to enjoy this experience," he told Cadena SER. "I am sharing the dressing room with the best in the world.
"Every Spanish player dreams about this and yet it is complicated. Few people can get to wear the shirt of the best team in the world.
"There are many absences, but there are still some great footballers in the squad. We will see if I am lucky and can play, whilst I am grateful to be called."
The forward revealed that he first heard the news via his brother before receiving official confirmation.
"I had a call from my brother," he added. "Then I received an email from the press officer at the Spanish Football Federation with the details of when I will join up."
Spain sit top of Group I, level with France on 14 points but with a game in hand.