What is, arguably, the only thing that could rally troops of Canadians to break out into singing the national anthem on the streets of the “True north strong and free” with “glowing hearts?”

Duh, beer, of course.

The clever marketing team over at Molson Canadian has made a few adjustments to the famous beer fridge that debuted at the Sochi Winter Olympics so that it will only open for those who can belt out the the lyrics to “O Canada” without tripping up.

The campaign is being launched in time for Canada Day July 1 and tests Canadian patriotism with the promise of a tricked-out fridge full of cold beer -- the country's national drink.

Flub up the lyrics, however, and the fridge will buzz angrily at the offender.

This past winter, the beer fridge was the talk of the Olympic Village and the envy of nations as it opened only to Canadian passport holders.

Are you a Canuck and need to refresh your memory? Brush up on the lyrics here.

Public service done.