The 25-year-old striker, who is only behind Cristiano Ronaldo in the La Liga top scorers charts, has hit 21 goals this season and is now expected to make an impact at the World Cup this summer after a drawn out debacle over his international allegiance.
Costa was born in Lagarto, Brazil, and earned two caps for Luiz Felipe Scolari's side in 2013, but they were both in friendly matches, meaning he could choose to play for Spain if he so wished - and after a stunning first half of the season for Atletico, Spain boss Vicente del Bosque decided to hand him a call-up, and Costa has now committed his international future to La Roja - as seen by the new picture below, showing the striker in the new Spain kit.
The news will come as a welcome boost to del Bosque, who has had problems up front for some time. Fernando Llorente moved to Juventus in the summer and has taken a while to get going in Serie A, but has hit 11 goals in the league for Juve - which may still not be enough to get him a place in Spain's World Cup squad.
Meanwhile, Roberto Soldado and Fernando Torres have both had difficult seasons in the Premier League for Tottenham and Chelsea respectively, meaning Costa's main rival for a place up front is likely to be Manchester City's Alvaro Negredo, who has enjoyed a prolific season under Manuel Pellegrini.
Playing for Spain in the World Cup in his homeland of Brazil is going to be a bizarre experience for the reported Arsenal, Chelsea and Manchester United target, but having banged in goals for Atletico this season, there will be plenty of expectation placed on Costa's shoulders this summer, as Spain chase a fourth successive major tournament win.