It’s called "The Greatest Outdoor Show on Earth" and this year’s centennial Calgary Stampede might just see its greatest attendance in history.

Spokesperson Jennifer Booth says they've already sold 60 per cent of their reserved tickets.

She said last year they didn't sell that many until opening day in July.

"There's a huge buzz in the air right now,” said Booth. “People have been getting excited about Calgary Stampede a lot earlier this year."

Tourism Calgary CEO Randy Williams says the media awareness surrounding Will and Kate at the Calgary Stampede in 2011 could draw bigger crowds to this year's event. (Charlie Riedel/Associated Press)

Booth credits a big marketing push by the Stampede and Tourism Calgary for the buzz about the centennial event.

Hotels in the city are also booking up earlier than usual.

"We were seeing bookings already in September of last year for this July, which is much earlier than we would normally see," said David Woodward with the Fairmont Palliser.

But Tourism Calgary CEO Randy Williams says the biggest boost likely came from last year's royal visit when photos of Will and Kate in white cowboy hats were seen around the world.

"$50 million of media awareness that Kate and Will created for Calgary is a huge benefit for us," he said.

Williams says it put the Calgary Stampede on the minds of people who had never heard of it before.