In back yards and lakesides this holiday weekend, tens of thousands of Minnesotans will keep a close eye on barbecuing meat.

People in Duluth can just watch TV instead.

Fast-food giant Arby’s, working with Minneapolis ad agency Fallon, is airing a commercial on a Duluth TV station that is 13 hours long and shows one thing for nearly the entire time: meat slowly cooking in a smoker.

The commercial begins at 1 p.m. Saturday on My9 TV in Duluth. In the last couple of minutes, which will be around 2 a.m. Sunday, Arby’s executive chef takes the meat out of the cooker and slices it into a sandwich.

The stunt will get Arby’s into the “Guinness World Records” for longest TV commercial, far surpassing an hourlong commercial that skin cream maker Nivea ran on Swiss TV in 2011. Next Wednesday, the commercial will be webcast on a site where viewers can participate in contests to win cash, sandwiches, barbecue equipment and other prizes.

More important for Arby’s and Fallon, it marks the start of an effort to call more attention to the quality of Arby’s food to distinguish the company from other fast-food chains.

Atlanta-based Arby’s hired Fallon in January to remake all its advertising. Getting some attention and sales for Arby’s Smokehouse Brisket Sandwich, a product that will be offered for only a few months, was an early priority for both firms.

“What we found when we started working with Arby’s is the food is the real deal. They have a legitimate food story,” said Rocky Novak, managing director at Fallon. “And so the approach we took is to focus on the food and convey, ‘We’re incredibly serious about our food but we don’t take ourselves too seriously.’ ”

When Fallon’s creative team learned that Arby’s distributes meat for the brisket sandwich to its restaurants after it’s been smoked at a Texas smokehouse, it decided to just tell that story.

The idea, Novak said, is that “We love our food so much we’re just going to look at it for 13 hours. We think any real lovers of barbecue will be rapt.”

Jeff Baker, senior brand experience director at Arby’s, said the idea for the commercial was an easy sell at the company. “We were focused on the authenticity and simplicity of it,” Baker said.

They hunted around for a TV station willing to sell 13 hours of airtime. Coming on a slow part of a holiday weekend, airtime was not particularly expensive, and they’ll spend more on prizes than for the broadcast, Novak said.

A sales representative for the Duluth TV station didn’t return a call for comment.

The project proved to be a technical challenge. The Texas smokehouse built a special smoker with a window large enough to show the whole slab of meat and with room for special lights inside. One attempt to make the commercial didn’t work when the smoke obscured the meat. A second attempt failed when there was trouble with the light.

“It’s funny to say, but it was kind of a high-risk shoot,” Novak said. “If the battery on the camera had run out at 12½ hours, we would have had to start over.”

For years, some TV and cable channels have broadcast images of fires in hearths during low viewing times at Thanksgiving or Christmas Eve. Networks in Norway have developed so-called “slow TV” shows that simply show ordinary events, such as a train going on its route or a salmon-fishing crew out on its run, in real time.

The executives said such precedents didn’t influence their 13-hour commercial, however.

“You could debate whether there is a lot of action when you are showing a stationary object and smoke for 13 hours,” Baker said.

But Novak said the commercial has its own sort of drama. “The beautiful moment when the bark starts to form on the meat itself is riveting.”