Mix the cream cheese, beef, olives, onion, and Worcestershire sauce together in a bowl until evenly blended. Keeping the mixture in the bowl, scrape it into a semi-ball shape. Cover, and refrigerate until firm, at least 2 hours.
Place a large sheet of waxed paper on a flat surface. Sprinkle with walnuts. Roll the cheese ball in the walnuts until completely covered. Transfer the cheese ball to a serving plate, or rewrap with waxed paper and refrigerate until needed.