Fill Listbox with 2 sheet columns.

Hi there,

I'm trying to populate a Listbox "listbox3" with two columns on a worksheet. These columns aren't set next to one another, therefore I cannot just assign a rowsource of "A:B" etc.. it would instead need to be "D" and "F".

I have started a piece of code (below) however not sure if I'm going about it the right way. Any advice would be greatly appreciated.

 Dim rngFirstNme As Range
Dim rngLastNme As Range

rngFirstNme = Sheets("pgs_CustomerList_Unique").Range("D2:D502").Value

rngLastNme = Sheets("pgs_CustomerList_Unique").Range("F2:F502").Value


Listbox3. ? = ?