After the co-owner of retailer L.L. Bean expressed support for President-elect Donald Trump, the future leader of the United States urged his 19.6 million Twitter followers to buy the company’s goods.

Trump tweeted:

“Thank you to Linda Bean of L.L.Bean for your great support and courage. People will support you even more now. Buy L.L.Bean.”

The unprecedented endorsement came less than two hours after Linda Bean said on a talk show early Thursday that anti-Trump groups are browbeating American businesses, an effort she called “un-American.” “It’s a case of bullying,” Bean said on “Fox and Friends.” “I’m not going to back down. I never back down.”

Bean, a granddaughter of L.L. Bean founder Leon Leonwood Bean, contributed $30,000 to a pro-Trump super-PAC called Making America Great Again LLC between August and October of last year, according to recently amended federal filings. Another $15,000 was contributed by Maine resident Diana Bean, the name of Linda’s sister.

The PAC, which also goes by Making Maine Great Again, ran a spate of TV and radio ads in the state toward the end of the campaign.

It was not until this month, however, that Linda Bean’s support for Trump burst into public view, when the Federal Election Commission alerted the group that it had erroneously formed as a traditional PAC, which can legally only accept donations up to $5,000.

That prompted Grab Your Wallet, a boycott effort against companies that carry Trump brand products or have other connections to the president-elect, to add L.L. Bean to its list. Organizers have said they will not take L.L. Bean off its website until Linda Bean is ejected from the board.

The company has asked for the boycott to be dropped, saying that the corporation has no connection to the PAC.

“We are deeply troubled by the portrayal of L.L.Bean as a supporter of any political agenda,” executive chairman Shawn Gorman posted on Facebook on Jan. 8. “L.L.Bean does not endorse political candidates, take positions on political matters, or make political contributions.”

Katherine DeCelles, a Harvard business professor who focuses on ethics, said no White House leader in modern history has used his platform to hawk products.

“It’s unprecedented,” she said, “for someone of his power voicing his support or being against particular companies.”

Federal employees are legally forbidden from endorsing private firms. Though the president is exempt from the rule and the president-elect is not a federal employee, such endorsements are largely frowned upon in America’s highest office.

In 2009, after a coat company used a photo of President Barack Obama in an ad campaign, Ben LaBolt, a spokesperson for the Obama administration, told The New York Times that, “the White House has a longstanding policy disapproving of the use of the president’s name and likeness for commercial purposes.”

Amanda Schreyer, an advertising and social media lawyer in Boston, said Trump’s tweet broke no laws Thursday. He’s entitled to free speech — but could face lawsuits if he distributes false information about a company and hurts their profit.

“It’s just poor form,” she said, “and for hundreds of years, it has been understood that the ruler of the land shouldn’t be picking and choosing which companies to endorse or otherwise.”

Since the election, Trump has made a practice of praising and chastising private companies. Last month, he slammed air conditioning company Carrier for moving jobs from Indiana to Mexico. He also has criticized several automakers for offshoring jobs and Boeing for the cost of its new Air Force One.

Washington Post writer Matea Gold contributed to this report.