The incident occurred during the half time break, postponing the start of the second half.
Paramedics rushed to his aid, but were unable to save him.
In a statement released this evening, Portsmouth FC said: ‘Despite valiant attempts by medical staff – who were quickly on hand to administer CPR – and following transportation to QA Hospital, he was unable to be revived.
‘Next of kin have been notified and are thoughts are with them at this time.’