Date Countdown with Reference to Specific Cell?

[Antligen]

Hi,

I have this formula counting down days until my next fire drill:

=DATEVALUE("17/12/2014")-TODAY()&" days until next fire drill is due"

However... Every time the drill is done I need to change the date in the formula for the countdown.

I don't want to have to manually change this formula EVERYTIME I do a drill. Is there away instead of having:

("17/12/2014")-

that I can have it reference a cell instead?

Myinitial idea was a formula like this:

=DATEVALUE(G10)-TODAY()&" days until next fire drill is due"

(however this code doesn't actually work ...)

Any ideas from the formula wizards out there?

Kindest regards as always,

Antligen