Hi again, drawing a circle sprite?

Unity Engine
1

I have this code, I want the shape of the picture of facebook profile to be circular instead of rect, is that possible?
and what can I do to do so?

regards.

    void DealWithProfilePicture (FBResult result)
    {
        if (result.Error != null)
        {
            Debug.Log ("problem with getting profile picture");

            FB.API (Util.GetPictureURL ("me", 128, 128), Facebook.HttpMethod.GET, DealWithProfilePicture);
            return;
        }

        Image UserAvatar = UIFBAvatar.GetComponent<Image> ();
        UserAvatar.sprite = Sprite.Create (result.Texture, new Rect (0, 0, 128, 128), new Vector2 (0, 0));
    }
2

You need UI Mask element
http://docs.unity3d.com/Manual/script-Mask.html
https://unity3d.com/learn/tutorials/modules/beginner/ui/ui-mask