Preheat the oven to 375°F and grease a shallow, 3-cup baking dish or ovenproof skillet with butter.
Mix the cream cheese, sour cream, lemon juice, Worcestershire sauce, Old Bay seasoning, and pepper. Use an electric mixer or a food processor to blend everything together. Transfer the mixture to a bowl.
Gently stir in the crab, green onions and celery.
Spoon the mixture into the prepared baking dish and spread it out evenly. Sprinkle shredded cheese on top.
Bake for about 22 minutes, or until bubbling.
While the crab dip is baking, melt butter in a skillet over medium heat. Add minced garlic and cook until fragrant, about 1 minute. Season the the shrimp with paprika and Old Bay seasoning, and add to the skillet. Cook until the shrimp are pink and just cooked through, about 3-4 minutes. Don't overcook!
Remove the crab dip from the oven and top with the cooked shrimp.
Return the dish to the oven and broil for 1-2 minutes. Lightly dust with Old Bay, sprinkle with minced green onions, and serve hot with sliced cucumbers, crostini and crackers.