Preheat oven to 400°. Squeeze juice from 1/2 of the orange; set aside.
Combine 1 tub Knorr® Homestyle Stock - Chicken, herbs, olive oil, orange juice and 1/4 teaspoon black pepper in small bowl. Rub mixture under and over turkey skin. Arrange remaining 1/2 orange and onion inside cavity of turkey. Arrange turkey in roasting pan on rack.
Roast turkey 45 minutes. Decrease oven to 375° and roast 1 hour. Baste turkey and turn pan in oven. Continue roasting until meat thermometer inserted in thickest part of thigh reaches 165°, about 1 hour. Remove turkey from pan and keep warm.
Meanwhile, bring reserved giblets, turkey neck, 4 cups water, celery, carrot and onion to a boil in 2-quart saucepan. Reduce heat and simmer covered 1 hour. Remove and discard vegetables and strain off 3 cups liquid. Use 1 cup to baste turkey and reserve 2 cups to make gravy.
To make gravy, combine reserved 2 cups liquid with flour in small bowl, then stir into pan over medium heat. Stir in port wine and remaining Stock, scraping up brown bits from bottom of pan. Cook, stirring frequently, until gravy is slightly thickened, about 5 minutes. Strain, if desired. Stir in cream and remaining black pepper. Serve gravy with chicken.