"As the CDC studies the spread of #COVID-19, they recommend people wear cloth face coverings in public settings when social distancing can be hard to do. Remember, this does NOT replace the importance of social distancing," the tweet read.
She appears to be the first member of the Trump family to publicly don a face covering and no other high-profile figures in Washington have been seen wearing one.
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The tweet with a still photo came after she posted a video of herself reading the CDC guidelines.
Holding up a white face mask and dressed in a white blouse, Trump said "cloth face coverings" can be worn in public settings "such as grocery stores and pharmacies."
"Remember: This does not replace the importance of social distancing … it is another recommended guideline to keep us all safe," she says, speaking straight to camera from a backdrop that appears to be an exterior window of the White House.
Her husband, however, has said that he won't wear one, suggesting he doesn't think it's presidential.
The president first announced last Friday that the CDC, in a reversal, was now advising Americans wear non-medical masks in public, adding it was voluntary.
Days later, at Sunday's briefing, asked about the first lady's support of face coverings, President Trump said she "likes the idea" while continuing to distance himself from the recommendation.
"It's good, no, she feels that way," Trump said. "She likes the idea of wearing it, yeah, she does. A lot of people do. Again, it's a recommendation, and I understand that recommendation, and I'm okay with it."
Although the first lady has released a handful of informational videos amid the outbreak, she has faced some criticism for not using her public platform in a potentially bigger way throughout the crisis. Though known to be a private person, she has 13.7 million followers alone on Twitter.
Perhaps aware of that criticism, her office has adopted a new practice in recent weeks of sending out readouts of calls she's conducted with counterparts on the global stage. In the last week, she has now spoken with her counterparts in Japan, Italy, France and Canada.
The choreography comes as Stephanie Grisham transitions back to the first lady's office and out of her job as the president's press secretary, though she remained the first lady's press secretary as well during that time.
ABC News' Ben Gittleson and Elizabeth Thomas contributed to this report.