He is a 38-year-old father of three who was working in a supermarket store in Nugegoda, police said.
He had gone to a party hall in Wewala, Piliyandala for his sister's wedding and was said to be in good health at the time.
A hospital spokesman said that he had fallen down during the ceremony and was taken to the Piliyandala District Hospital where he succumbed to his injuries.
The body underwent the postmortem examination following PCR testing. An autopsy revealed that he had died of a heart attack.
The Piliyandala Police are conducting further investigations.