I need to show the content of a specific cell in the custom page header when
I print my worksheet.

I'm sure it can be done because I did it way back in Excel 95 or 97, but I
can't find the right search term to locate it in the help, and the wizard
guidance only helps me put file/sheet/date/page data values in there.

So, how do I get the content of cell $D$1 to appear as part of the page
header?