Gallagher Hospitalized For Heart Attack

65-year-old Gallagher was walking towards the stage with another person when he stopped suddenly and collapsed. Emergency personnel responded to the scene and transported Gallagher to a nearby hospital.

Gallagher's manager tells TMZ ... the comic suffered a "mild to serious" heart attack and will remain in the hospital for the next couple of days while doctors try to figure out what's wrong with his ticker.