Round Masks

Hello all,

I have a question regarding masks.

For example, I need a circle mask attached to an object in order to reveal the background (images attached for reference).

I couldn’t figure out yet how to create just a circle mask - without the remaining square outline, like in the 3rd screenshot.

(other than perhaps create a much more larger mask image to cover to whole object area - in this case, the yellow coin)

Screenshots attached explain best.

First image - Initial

Second image - Wanted result

Third image - Unwanted result (current situation)

Thanks a lot,

Radu