Sen. Bernie Sanders will receive an endorsement from Democratic star Rep. Alexandria Ocasio-Cortez at a rally in New York City on Saturday, according to sources in the Sanders campaign.

The event — dubbed “Bernie’s Back” — will be the first rally Sanders has held since his campaign revealed that he suffered a heart attack a few weeks ago while on the campaign trail. The endorsement comes at a pivotal time as Sanders loses momentum in national polls.

Former Ohio State Sen. Nina Turner, a national co-chair of the Sanders campaign, confirmed Tuesday night that Ocasio-Cortez (D-N.Y) will be the special guest at the Queens rally and that she will endorse him for president.

She said it stands to reason, because Sanders' progressive history has enabled candidates like Ocasio-Cortez to be unabashedly progressive on the national stage. Now, she can return the favor by lending Sanders some millennial energy.

"For all the haters who say that he's not a feminist enough, all the haters who say he's too old, she brings that youthfulness with her to complement what he already did in 2016," she told VICE News after the Democratic debate in Ohio. "He already brings the thunder. ... This just takes him to the next level."

Sanders backed Ocasio-Cortez’s long-shot bid last fall to unseat a member of the Democratic leadership, Rep. Joe Crowley. The two have teamed up on legislative efforts since she joined the House of Representatives in January.

Still, she is close with Sen. Elizabeth Warren as well, and had shown signs publicly that she could endorse the Massachusetts Democrat.

Cover: Representative Alexandria Ocasio-Cortez (R), Democrat of New York, speaks alongside US Senator Bernie Sanders (L), Independent of Vermont, during a press conference to introduce college affordability legislation outside the US Capitol in Washington, DC, June 24, 2019. (Photo: SAUL LOEB/AFP/Getty Images)