Barcelona midfielder Gavi says the Spain squad were shocked to find out that defender Marc Cucurella had signed for Real Madrid.
Former Barça academy graduate Cucurella joined Madrid from Chelsea in a deal worth an initial €55 million earlier this week.
Cucurella, 27, is currently at the World Cup with Spain but had not given anything away to his international teammates.
"We only found out in training the day before, well, just after the session," Gavi told RAC1.
"No one knew. He had kept it quiet, the bastard. We didn't expect it."
Sources told ESPN that Barça had sounded out a possible move for Cucurella in April but never developed their interest due to having other priorities.
Atlético Madrid were also keen on the left-back, but Madrid moved quickly to tie up the signing after appointing José Mourinho as the club's new coach last week.
Given Cucurella's Barça past, it will add an extra layer of spice to next season's Clásicos as he becomes the only Madrid player in the Spain squad in North America.
"Now he has to defend against Lamine [Yamal]," Gavi added. "[Madrid] have changed full-backs a lot in recent years, it's very hard to stop Lamine -- I hope he remains unstoppable.
"But it will be nice. I like Cucu as an opponent. He's tenacious, he's intense... he's a good signing for Madrid and I am happy for him."
There has been some backlash from Barça fans online to Cucurella's decision to join Madrid, but he says it was an opportunity he could not turn down.
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"You have to respect people's opinions," Cucurella said of the criticism in a news conference on Thursday.
"I'm very grateful for everything the Barcelona academy gave me. But like everything in life, it's about stages.
"I thought this was the right decision to take. When a team like Madrid come to you, it's very hard to turn down. I had no doubt it was the right step."
Cucurella and Spain are next in action when they face Saudi Arabia in Group H on Sunday in Atlanta.
Spain are looking to secure their first win of the World Cup after being held to a shock goalless draw by Cape Verde in their opening fixture.