Fortunately, the Spain world cup winner's condition is said to have stabilised and is out of any imminent danger after being taken into care earlier in the day.
According to Independent the veteran keeper was taken from the field feeling unwell during Porto training.
Maisfutebol, reports that Casillas underwent surgery but is now conscious and out of harm's way.
The Spaniard suffered a myocardial infarction and was subjected to cardiac catheterization — the insertion of a catheter into chamber or vessel of the heart.
Casillas started his career at Real Madrid in 1990 playing for the junior team.
He joined the senior team in 1997, made his debut the following season (1998).
The Spanish international has won two champions league and five La Liga titles.
Casillas name is in history books as the third captain after Franz Beckenbauer and Didier Deschamps, to win the World Cup, the Champions League trophy and the European Championship trophy.
More to follow...