Wendy's is working with longtime agency Ketchum on the rollout of the Pretzel Bacon Cheeseburger, the pub-style hamburger tested earlier this year that's drawn online and media interest.

burgerThe fast food chain said the cheeseburger outperformed any other promotional burger in the company's history. Chief marketing officer Craig Bahner called the offering the "ultimate mash-up of three American loves – pretzels, bacon and cheeseburgers."

The Associated Press sparked interest in January when it reported on the test offering and published a photo of a promotional poster on a visit to a Miami Wendy's. Photos of the burger were circulated on social media by patrons who visited restaurants included in the test.

But Wendy's took a cryptic approach about the burger as word leaked out about the tests, declining the comment. Senior VP of communications Denny Lynch told an inquiring USA Today last month, "We're not sharing details of this sandwich today. It's not in any of our restaurants." 

Nation's Restaurant News said news of the burger's likely introduction this year provoked one analyst to upgrade his outlook for Wendy's stock.

The AP's Candice Choi reported in May that the new burger is part of Wendy's push toward more premium breads, which give its burgers a "higher-quality veneer that let's Wendy's charge higher prices." MSN Money's Jonathan Berr said the pretzel burger comes as Wendy's tries to market itself as a higher-quality alternative to its fast-food rivals, with mixed results so far.

Wendy's said the burger is being rolled out over the next two weeks through July 4 and will be available all summer in the U.S. and Canada.