Userform VBA - VLookup Data Range From One Workbook And Populate Into Another Workbook

what VBA is required to have a combo box in a userform look up data in a different workbook, then populate that data into the drop down list of that combo box for a user to select.

I have managed to successfully create a vlookup for a combo box in a userform that looks up data in a named range in another worksheet within the same workbook and then populate that data into a field in a worksheet within the same workbook. However, I want to change this so the combo box on a userform (in one workbook) will look up data from a named range in a second workbook without opening the second workbook. At the moment, the code I have that will 'submit' the user selected data from the combo box drop down list works.

The code that has worked so far to vlookup data for the combo box from a worksheet within the same workbook is:

Code:
Private Sub UserForm_Initialize()
Dim pName As Range
Dim ws As WorksheetSet ws = Worksheets("vlookupsheet")
For Each pName In ws.Range("ProjectName")
With Me.cboProjectName
.AddItem pName.Value
End WithNext pName
Me.cboProjectName.SetFocus
End Sub

Do I need specify the file path of the second workbook that will contain the data for the combo box as well as the name of the worksheet and named range in that second workbook?