Merging objects, please help

hay guys, im still pretty new to blender, im working on an iron man helmet (picture below) and need to add the circular ear things to the overall mes, i was wondering what is the best way of merging the two objects together and still have the circle look like a circle

Join (CTRL+J). Both the circle and the rest of the mask will remain as they are, but you’ll have to make new faces (F) to fill in between.
It would be easier to use a circle with less vertices. Since the “ear” location you have is made of 15 vertices, you could use a 15 vertex circle.