Rep. Alexandria Ocasio-Cortez (D-N.Y.) will endorse Sen. Bernie Sanders (I-Vt.) for president as she appears alongside him at a rally in New York City on Saturday, the Washington Post first reported.

Why it matters: It's a major coup to be endorsed by a members of the influential "Squad," especially as Sanders was starting to flag in the 2020 election polls.

Ocasio-Cortez, who worked on Sanders' 2016 presidential campaign, in particular holds great influence and has 5.5 million Twitter followers.

Rep. Ilhan Omar (D-Minn.) confirmed in a statement Tuesday night that she was endorsing him. CNN reports that fellow "squad" member Rashida Tlaib (D-Mich.) would also endorse him when the 3 rising Democratic stars were expected to appear at the rally.

What they're saying: When asked for official confirmation by Axios political reporter Alexi McCammond, Ocasio-Cortez's spokesman Corbin Trent would only say, "We're very excited for Saturday."

The big picture: Axios' Zachary Basu noted that 78-year-old Sanders "exuded his usual high energy" on Tuesday night, in his first Democratic debate appearance since being treated in hospital this month for a heart attack.

Sanders had vowed earlier to return to a "very vigorous campaign," and Saturday's rally looks set to be electrified by his latest endorsements. He teased during Tuesday's Democratic debate and on Twitter that there would be a "special guest" at his New York rally.

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Editor's note: This article has been updated with new details throughout.