Message Box with a formula result for hidden columns

I have the following code, which has a formula in it that brings back the column name. What I would like to do is to find out which column(s) is hidden. It might just be a silly syntax error but the message box brings back the actual formula, not the result of the formula.

Sub HiddenColumns()
Dim i As Long
For i = 2 To 12
If Sheets("Comments").Columns(i).Hidden Then
MsgBox "=CHAR(COLUMN()+64)"

End If
Next i

End Sub