According to Maisfutebol, Costa suffered a cardiac arrest in the morning while attending the training session of Porto's first team.
It was then confirmed later this afternoon that he had passed away at Sao Joao Hospital in Porto.
In a statement, the club said: "Porto expresses its deepest sadness and consternation at the passing of an inescapable figure in the Club's history. Throughout his life, on and off the field, Jorge Costa embodied the values that define FC Porto: dedication, leadership, passion, and an unwavering spirit of conquest. He influenced generations of fans and became a major symbol of Porto.
"In this time of immense grief, Futebol Clube do Porto extends its deepest condolences to Jorge Costa's family, his friends, and all who shared unforgettable moments with him."
Correio da Manha added that Costa was immediately assisted on the spot by the side's medical team, and they even had to use a defibrillator.
It should also be noted that moments before, the former Portuguese international had been speaking to the microphones of SportTV, emphasising the harmony between the Porto club and its fans.
This is the second time that the former club captain has had a heart problem, after he suffered a heart attack in 2022, shortly after leaving his post as coach of Tunisian club Sfaxien. He eventually recovered after undergoing a catheterisation.