Add boiling water to gelatin mix in large bowl; stir 2 min. until completely dissolved.
Add enough ice to cold water to measure 1 cup. Add to gelatin; stir until slightly thickened. Remove any unmelted ice.
Whisk in COOL WHIP until blended.
Refrigerate 15 to 20 min. or until mixture is thick enough to mound.
Spoon gelatin mixture into crust.
Refrigerate 4 hours or until firm.
