Bolton midfielder Fabrice Muamba was rushed to hospital after collapsing during the first half of his team's FA Cup quarter-final against Tottenham at White Hart Lane.
With 41 minutes on the clock, Muamba suddenly dropped to the floor and six paramedics ran on to the pitch moments later to treat the 23-year-old.
The paramedics tried to resuscitate the player while players and fans, many of them in tears, looked on.
A Bolton spokesman said: "Fabrice Muamba has been taken to hospital following his collapse.
"There is no further information at this time."
Bolton boss Owen Coyle shouted "he's just collapsed" before running across to join the paramedics.
A defibrillator was used on the star, who has also played for Arsenal and Birmingham.
Muamba, 23, was carried off on a stretcher after receiving six minutes of treatment.
He was wearing an oxygen mask and was flanked by a number of paramedics and Bolton medical staff.
Shortly after he left the pitch, referee Howard Webb took the players off the pitch and the game was abandoned.