Customers at the Tim Hortons in Edmonton’s Royal Alexandra Hospital are the latest to benefit from free coffee purchased by mostly anonymous benefactors.

A man believed to be a worker at the hospital bought 500 cups around 8:30 Thursday morning.

Then a woman whose elderly father is a patient at the hospital bought 800 cups after hearing about the earlier act of generosity.

"It’s a way to give back," Monica Kavanaugh said. "They've (hospital staff) helped my father a lot and I just feel, why not give a little back to the hospital?"

The trend started on Monday when a mystery man walked into a downtown Edmonton Tim Hortons and bought 500 cups of coffee.

The next day, another 500 cups were purchased at the Crowfoot Tim Hortons in Calgary.

The trend spread east on Thursday when a man believed to be a transit employee paid for approximately 500 cups at an Ottawa location. Hundreds of free coffees were also purchased at Tim Hortons in Red Deer.

The trend has raised suspicions that the mysterious strangers are part of a marketing campaign for the coffee chain. But Tim Hortons spokeswoman Michelle Robichaud says that isn’t the case.

"Absolutely not," Robichaud said.

"We’re just as surprised and thrilled as our guests have been by these incredible random acts of kindness .. our only role is really in pouring the cups of coffee."