Monaco continue to build towards the 2018-19 Ligue 1 season by completing the signing of Pele.
The 26-year-old joins from Rio Ave and is likely to replace Fabinho following the midfielder's move to Liverpool.
Pele, a Guinea-Bissau international, won Rio Ave's player of the season award last campaign.
"I am very happy to join Monaco, an ambitious club competing in the Champions League and a contender in Ligue 1," Pele told the club's official website.
"It's great motivation and a dream to represent Monaco. I cannot wait to meet the staff and my team-mates."
Although Fabinho and Thomas Lemar have left the club, Monaco have made signings including Barcelona teenager Robert Navarro and Chelsea youth prospect Jonathan Panzo for the new season.