Help - translucent countdown timer for iMovie?

[Baron58]

I want to make a short video (some movie clips, some photos, transitions, voiceover). I want it to be (for example) exactly 60 seconds, and would like to have a small digital countdown timer in the lower right corner of the screen, overlaying everything, that will count down the length of the clip, 1:00 :59 :58 :57....

I'm sure there's no way to do thiis without a third-party plugin, but haven't been able to find anything that does what I'm looking for. Does anyone have any leads?

Thanks,