Burger King did a rare thing earlier this month in Argentina--it directed customers to rival McDonald's.

The reason? On Nov.10, McDonald's Argentina was "McHappy" day, when all sales from Big Macs are donated to help children with cancer. So on that day, all 107 Burger King restaurants refused to sell its Whoppers and encouraged people to go to McDonald's instead. The stunt, by agency David, was of course filmed in a video that shows just how generous BK was being (rather than, say, just making a quiet donation itself).

It's not the first time BK has reached out to the Golden Arches--in 2015 it won several Grand Prix at Cannes for its McWhopper campaign, by Y&R New Zealand, that offered to combine the Big Mac and Whopper for Peace Day.