Add vertical line to mark current day

Hi, is it possible to add a line to a chart based on a measure. I am hoping to acheive the equivalent of a constant line (vertical dashed line) which reflects the day in the month of today's date.

I have managed to add a pointer to the current chart but it''s not ideal as I was hoping for a constant vertical line (which shifts each day when report refreshed).

DAX code is here for the current day marker: 

Current Day Marker = IF(MAX('FactsheetApproval'[DayOfMonth2]) = DAY(TODAY()), 3, 0)

I tried it via the X-axis constant line settings but the marker is stuck at zero when i do this:

Any thoughts? Thanks in advance.