The 24-year-old defender will move to the King Power Stadium on a five-year deal for an undisclosed fee, believed to be in the region of £20million.
Starting his career at Sporting Club de Portugal, Pereira progressed through the academies of Naval and Vitoria Guimaraes, before making his professional debut for the latter. He switched to Porto in 2013.
He has played under Foxes boss Puel before having enjoyed a two-year loan switch at OGC Nice under the Frenchman between 2015 and 2017, playing in the Europa League.
The three-time Portuguese international has enjoyed a fantastic campaign back at the Estádio do Dragão this season having made 43 appearances in all competitions including seven in the UEFA Champions League. In that time, he has managed to score twice and provide seven assists as Porto lifted the Primeira Liga under Sérgio Conceição.
Fernando Santos also named him in his 23-man Portugal squad for the upcoming World Cup in Russia.
'I feel very happy'
Upon penning his contract with the former Premier League champions, Pereira expressed his delight. He said: “I feel very happy to be here and I can’t wait to do my best to help the team. I am here to support the team and to help the Club to achieve its goals.”
Puel also gave his thoughts on the capture of the talented defender. He said: "I’m delighted to have a player of Ricardo’s quality on board for next season. I remember him well from my time at Nice.”
Pereira will officially become a Leicester City player on June 9th and will link up with his team-mates after the conclusion of the World Cup.