Autumn Apple Salad

1 can (20 ounce) crushed pineapple, undrained
2/3 cup sugar
1 package (3 ounce) lemon-flavored gelatin
1 package (8 ounce) cream cheese, softened
1 cup diced unpeeled apples
½ to 1 cup chopped nuts
1 cup chopped celery
1 cup whipped topping

In a saucepan, combine pineapple and sugar; bring to a boil and boil for 3 minutes. Add gelatin; stir until dissolved. Add cream cheese; stir until mixture is thoroughly combined. Cool. Fold in apple, nuts, celery and whipped topping. Pour into a 9 inch baking dish. Chill until firm. Cut into squares and serve on lettuce leaves.