Line a 9x5 inch loaf pan with foil. Spoon the two cups of softened lime sherbet into the loaf pan. Spread the sherbet out evenly in the pan and freeze the pan for 10 minutes.
Whisk the cream cheese spread in a large bowl until creamy. Gradually whisk in the sweetened condensed milk then add the lemon juice and whisk until blended. Stir in the thawed Cool Whip until there are no lumps. Spread the mixture over the sherbet layer in the pan. Freeze for 3 hours. Right before serving, remove the pan from the freezer. Unmold the dessert onto a serving plate and slice to serve.