Roughly peel and then juice the orange. Stone and peel the mango.
Transfer the orange juice and mango to a food processor or blender, add the milk and process until smooth. Pour the mixture into a glass.
Put the strawberries in the food processor or blender with 1 tablespoon of water and process until smooth.
Pour the strawberry mixture into the glass on top of the mango mixture. Stir a little to create swirls of the strawberry mixture in the smoothie.