Steven Spielberg's 1982 classic ET
Mathison, who is known for her screenplay in Martin Scorsese's directorial, 'Kundun', had died due to an illness, the Guardian reports.
In a statement, Spielberg, who has worked closely with Mathison on ET said, "Melissa had a heart that shined with generosity and love and burned as bright as the heart she gave ET."
Mathison was married to actor Harrison Ford in March 14, 1983 and the couple had first met on the set of 'Apocalypse Now'.