Problem with servomotors


I have 2 servomotors(MG996R) and I need to use 2 separate batteries to supply each servo motor, do I have to connect the 2 grounds of those batteries to the ground of the arduino uno that I want to use to control my servos or I can just use them directly?


All of the grounds need to be connected together. Battery grounds (- side) and servo grounds to Arduino ground.

Thank you a lot for your help