On Monday afternoon, a man in his mid-20s walked into a downtown Edmonton Tim Hortons and ordered a double-double and a Boston cream doughnut.

Then he asked the cashier how many coffees she typically sells in a day — and asked her to ring in an additional 500 large coffees.

The bill came to $895.28, which he paid with a debit card.

"The manager asked him if he was going to drink all those coffees or was he going to give it to someone?" store manager Joanne Averion told the Canadian Press. "He said, 'You have to give it to the next 500 customers.'"

He gave no explanation for his act of generosity and promptly left the store.

"He didn't say anything, he just did it for no reason," Averion told Metro Edmonton.

He didn't leave his name either.

"We asked him his name and he didn't tell us," hostess Pinky Lung told CBC's Lisa McGregor. "He said he didn't want to tell anyone."

By 8:30 a.m. on Tuesday, the store had surprised 500 customers with free large coffees.

Averion told the Canadian Press that while the kind stranger wasn't the first person to pay for free coffees before, "Five hundred free coffees is definitely a first."