Scoop pomegranate arils and juice into a bowl. Set aside.
Heat oil in a paella pan or cast iron fry pan. Add chicken and season with salt and pepper. Add chorizo and onion and cook until chicken is browned slightly.
Add garlic and rice and cook, stirring for 1 minute.
Add stock, tomatoes, saffron water and threads and cover loosely with foil. Bake at 170°C, stirring occasionally till liquid is absorbed and rice is cooked, about 35 minutes. Add olives and peas and cook uncovered for a further 5 minutes.
Serve at the table in the pan it was cooked in. Sprinkle with pomegranate arils and juice just prior to serving.