Porto goalkeeper Iker Casillas has been rushed to hospital after suffering a suspected heart attack in training.
The 37-year-old left the training field when feeling unwell on Wednesday morning before being taken to hospital for emergency surgery.
Portuguese media outlet Maisfutebol reports that Casillas is now conscious and out of danger having undergone a cardiac catheterisation.
Casillas has played more than 1,000 games for club and country during an illustrious career which has seen him become one of the most decorated players of his generation.
The Spain legend made an unrivalled 167 appearances for his country, leading them to the most successful spell in international football history by winning two European Championships and the World Cup between 2008 and 2012.
Casillas spent 25 years at Real Madrid before moving to Porto in 2015, making more than 700 first-team appearances for the club and helping them to five La Liga titles and three Champions Leagues.
Considered one of the greatest goalkeepers of all time, Casillas has also played in more Champions League matches than anyone else.