New York Rep. Alexandria Ocasio-Cortez is set to endorse Vermont Sen. Bernie Sanders for president at a Saturday rally in Queens, the campaign confirms to NPR's Scott Detrow. It will be Sanders' first campaign event since he had heart attack earlier this month.

Sanders teased the event during Tuesday's Democratic debate, saying there would be a "special guest" attending.

She joins another member of "The Squad" — as a quartet of freshmen progressive women have come to be known on Capitol Hill — in backing Sanders. Minnesota Rep. Ilhan Omar announced Tuesday evening she is also endorsing the Vermont senator.

Ocasio-Cortez rose to fame last year after upsetting House Democratic Caucus Chairman Joe Crowley in the primary. Like Sanders, the 30-year-old Ocasio-Cortez is a self-described Democratic socialist and shares several policy priorities with the 78-year-old Sanders, including Medicare for All and the Green New Deal.

"Bernie is leading a working class movement to defeat Donald Trump that transcends generation, ethnicity, and geography," Omar said in astatement. "That is why he is fighting to cancel all student debt. That is why he is fighting to make all school meals universal. That is why he is fighting for a humane immigration policy that treats immigrants as human beings and not criminals. And it's why Bernie is fighting to end our forever wars and truly prioritize human rights in our foreign policy–no matter who violates them. And it's why I believe Bernie Sanders is the best candidate to take on Donald Trump in 2020."

Ocasio-Cortez and Omar — along with Michigan Rep. Rashida Tlaib and Massachusetts Rep. Ayanna Pressley — have attracted attention since they arrived in D.C., both for their progressive stances and their historic elections. And they've also become targets of President Trump. This summer, Trump derided them on Twitter, suggesting they were anti-American and should "go back" to the "crime infested places from which they came." All four women of color are American citizens, and all but Omar were born in the U.S.

The freshman congresswomen, who are popular with the party's liberal base, could provide a needed jolt to Sanders. He's been passed in the polls by Massachusetts Sen. Elizabeth Warren, who also has an influential progressive following.

And after he suffered a heart attack two weeks ago, which resulted in two stents inserted to address a blocked artery, there are new questions about his viability for office given both his health and age.

At Tuesday's debate, Sanders dismissed questions about his health, saying "we are going to be mounting a vigorous campaign all over this country."

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