squeaking noise when not pressing brakes

Hi guys! It just happened to me that on my drive back home, the car made a very hard squeaking noise when im not pressing the brakes. Eventually the noise got "better" (sometimes it happened sometimes not) Could this mean worn break pads? The car is already due to be serviced in a week at the Hyundai dealership, should i call them and tell them about this / or they probably have the components in stock so I should only tell them when i drop the car off? Thank you for the responses, have a nice day!:)