Tilføje sheets i en excel fil

Jeg opretter et excel dokument på denne måde, men kunne godt tænke mig at tilføje et ekstra art i excel.
Min kode ser sådan ud.

            //Start Excel, and then create a new workbook.
            xlApp = new Excel.Application();
            xlBook = xlApp.Workbooks.Add(Missing.Value);
            xlBook.Windows.get_Item(1).Caption = "XL Event Test";
            xlSheet1 = (Excel.Worksheet)xlBook.Worksheets.get_Item(1);
            xlSheet2 = (Excel.Worksheet)xlBook.Worksheets.get_Item(2);
            xlSheet3 = (Excel.Worksheet)xlBook.Worksheets.get_Item(3);
           
            xlSheet1.Activate();

            //Add an event handler for the WorkbookBeforeClose Event of the
            //Application object.
            EventDel_BeforeBookClose =
              new Excel.AppEvents_WorkbookBeforeCloseEventHandler(BeforeBookClose);
            xlApp.WorkbookBeforeClose += EventDel_BeforeBookClose;

            //Add an event handler for the Change event of both worksheet objects.
            EventDel_CellsChange = new Excel.DocEvents_ChangeEventHandler(CellsChange);

            xlSheet1.Change += EventDel_CellsChange;
            xlSheet2.Change += EventDel_CellsChange;
            xlSheet3.Change += EventDel_CellsChange;

            //Make Excel visible and give the user control.
            xlApp.Visible = true;
            xlApp.UserControl = true;