The Real Madrid defender has welcomed the Atletico star to la Roja and insisted club loyalties are left aside during international call-ups
The Brazilian-born forward, who could make his debut versus Italy on Wednesday, has been in stellar form for Atletico Madrid this season and has long been linked with a spot in Vicente del Bosque's squad.
Costa and Ramos went head-to-head in the Madrid derby draw on Sunday, but the defender insisted that club loyalties are put aside during the international window and he says he is excited to work with Rojiblancos players.
"I think Costa is a great choice and can bring many things," Ramos, 27, told AS. "There’s no problem between us. It’s part of our sport, we defend our interests.
"Football is to unite, not separate. We’re team-mates now.
"We know [Atletico Madrid] have a strong character and heart and that’s part of their style. Madrid’s is to control the ball more. They defend their thing and we defend ours.
"It’s good to have another team that can challenge for the title. They are doing very well and are at a high level."
A late Cristiano Ronaldo equaliser helped Real draw 2-2 at Atletico on Sunday but, despite earning a point to stay top of La Liga, Ramos believes the title-race is far from over.
"Yesterday our confidence dropped after the first goal. I’ll take the second half though," the Spaniard continued. "I don’t think we deserved more than a draw.
"[La Liga] is still very open. We have a small lead. We started the year very strong and now have to go game by game to increase that distance.
"I’m proud to play in this league. For me it’s the best in the world. Atleti are also hopeful of winning it."