Wolves are looking for reinforcements to move off the foot of the table as the Premier League makes a return on Boxing Day.
Cunha joined Atletico Madrid from Hertha Berlin in August 2021 and scored seven goals in 37 appearances across all competitions but has seen his minutes reduced this season, failing to score in 17 appearances.
Wolves have agreed a deal with Atletico to sign Cunha on loan until the end of the season with an obligation to make it permanent for £34m at the end of the season.
Lopetegui announced Cunha's imminent arrival in a press conference previewing Wolves' upcoming Premier League game against Everton.
"Today I have to talk about [Cunha]," said Lopetegui.
"It's clear he is going to be with us. It is going to happen once the market is open.
"Now, of course, he's going to be our player, but [for] the next matches, we have to focus on the players that are here. They have to play against the rest of the teams.
"He's a good player. I know him, and I think he's a good signing for us for the present and also for the future.
"He is a very complete forward. He has a good condition, good skills, not only technically but physically. This is England, and in the Premier League you have to be a very complete forward if you want to survive.
"I think he has this profile to play here for a lot of years. Of course, we are going to help him to develop his strengths in the future."
Cunha has won eight caps for the Brazil national team but was not included in their squad for the Qatar 2022 FIFA World Cup.
