Cook the spaghetti according to package instructions until al dente. Drain and set aside.

In a mixing bowl, combine softened cream cheese, sour cream, mozzarella cheese, Parmesan cheese, minced garlic, Italian seasoning, salt, and black pepper. Mix until smooth.

Add the cooked spaghetti to the cream cheese mixture and stir until the pasta is evenly coated.

Pour the marinara sauce over the pasta and mix gently to combine.

Transfer the spaghetti mixture to a greased baking dish. Top with additional mozzarella and Parmesan cheese.

Bake in a preheated oven at 350°F (175°C) for 25-30 minutes or until the cheese is bubbly and golden.

Remove from the oven, let cool for a few minutes, then serve warm.