Even investors are licking their chops over Popeyes’ chicken sandwich.

A Wall Street researcher raised his outlook for Popeyes third-quarter sales after determining that the fried chicken seller doubled its foot traffic last month — thanks to the now sold-out offering.

KeyBanc analyst Eric Gonzalez said Popeyes’ much-hyped chicken sandwich accounted for 30 percent of the fast-food chain’s sales during its limited run last month.

Just one week into the sandwich’s Aug. 12 launch, Popeyes started selling about 1,000 units daily at each of its 2,500 domestic stores, Gonzalez wrote in a Sept. 8 report.

The analyst lifted his third-quarter same-store sales target by 8 percent as a result.

The surge in demand was driven in large part by a Twitter exchange Popeyes had with Chick-fil-A roughly a week into its launch, Gonzalez said.

“… y’all good?” Popeyes wrote in response to Chick-fil-A’s tweet: “Bun + Chicken + Pickles = all the [heart] for the original.”

That triggered what Gonzalez called “a social media firestorm estimated to be worth tens of millions of dollars in free publicity for the brand.”

Popeyes, founded in New Orleans in 1972, blew through what it thought was seven weeks of inventory in less than two weeks. It has yet to bring the sandwich back.

The Restaurant Brands International unit also increased its Twitter follower base from 100,000 to 180,000 over the same period, effectively spoiling the much-hyped promotions of larger competitors.