WESTERVILLE, Ohio — Representative Alexandria Ocasio-Cortez of New York, a star of the progressive left, plans to endorse Senator Bernie Sanders of Vermont for the Democratic presidential nomination, Mr. Sanders’s campaign said Tuesday night.
Ms. Ocasio-Cortez will appear at Mr. Sanders’s “Bernie’s Back” rally in Queens on Saturday. Earlier Tuesday, his campaign had teased that Mr. Sanders would have a “special guest” at the event.
The planned endorsement was first reported by The Washington Post, as the Democratic presidential candidates were wrapping up their appearances in the fourth debate of the primary season.
News of the endorsement comes just two weeks after Mr. Sanders suffered a heart attack in Las Vegas. Since then, he has been recovering, first at a hospital and then at his home in Burlington, Vt.
The endorsement by Ms. Ocasio-Cortez, among the most influential and visible progressives in the country — and also one of the youngest people ever elected to Congress — will provide a much-needed boost to Mr. Sanders’s campaign. It could also serve to quell some concerns about his health and his age.
The on Tuesday night in Westerville, Ohio, just outside of Columbus, was Mr. Sanders’s first appearance before a national audience since his heart attack.
Mr. Sanders’s health issues have cast a degree of uncertainty over his campaign and left his aides rushing to reassure voters about his age and health, just as he was trying to improve his standing in a race that in recent weeks has become more of a two-person contest between Senator Elizabeth Warren and former Vice President Joseph R. Biden Jr.
Asked about his health directly at the debate on Tuesday night, Mr. Sanders nodded to the rally and to the “special guest.”
“Let me invite you all to a major rally we’re having in Queens,” he said. “We’re going to have a special guest at that event, and we are going to be mounting a vigorous campaign all over this country.”
He also said, “I’m feeling great.”
Mr. Sanders’s campaign is billing the New York rally as his official return to the campaign trail. It had toyed with holding the rally in Prospect Park, according to an aide, but settled on a park in Queens, with a backdrop of the Manhattan skyline.
This is a developing story and will be updated.
Matt Stevens contributed reporting.