Rep. Alexandria Ocasio-Cortez will endorse Sen. Bernie Sanders for president, The Washington Post reported on Tuesday night.

Reps. Rashida Tlaib and Ilhan Omar, two other members of the so-called "Squad" of progressive freshman congresswomen, will also endorse Sanders, CNN reported Tuesday night.

The endorsement is unexpected and will likely give Sanders a boost as his campaign gets back on its feet following his recent heart attack.

Ocasio-Cortez's endorsement is something of a surprise as she has previously expressed support for both Sanders and Sen. Elizabeth Warren.

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Rep. Alexandria Ocasio-Cortez will endorse Sen. Bernie Sanders at a campaign rally on Saturday just outside her home district in Queens, New York, The Washington Post reported on Tuesday night.

The endorsement is unexpected and will likely give Sanders a boost as his campaign gets back on its feet following his recent heart attack. Sanders touted his "special guest" at Saturday's "Bernie's Back" rally on Tuesday night.

"We're looking forward to Saturday," Corbin Trent, Ocasio-Cortez's campaign spokesperson, told The Post.

Ocasio-Cortez's endorsement is something of a surprise as she has previously said she's far from making an endorsement in the 2020 race. She has also praised Sen. Elizabeth Warren, who will likely be hurt by Ocasio-Cortez's support of Sanders.

Ocasio-Cortez has co-sponsored legislation with both Sanders and Warren. But when it comes to key policy issues, most notably healthcare, the Bronx native has overlapped more with her fellow democratic socialist.

Read more: Alexandria Ocasio-Cortez, who is backing Bernie Sanders in 2020, is the most coveted 2020 endorsement besides former presidents

Reps. Rashida Tlaib and Ilhan Omar, two other members of the so-called "Squad" of progressive freshman congresswomen, will also endorse Sanders, CNN reported Tuesday night. Rep. Ayanna Pressley, the fourth member of the squad, has not indicated whether she'll endorse a 2020 candidate at this point in the race.

"Bernie is leading a working class movement to defeat Donald Trump that transcends generation, ethnicity, and geography," Omar wrote in a press release on Tuesday night confirming her endorsement. "I believe Bernie Sanders is the best candidate to take on Donald Trump in 2020."

Sanders has worked with Ocasio-Cortez on a bill to cap credit card interest rates and with Omar on a universal school meals program and legislation to eliminate all student debt, which amounts to $1.7 trillion.

Ocasio-Cortez has also been complimentary of other 2020 candidates, including former HUD Sec. Julian Castro, who she tweeted was telling "the straight up truth" during Tuesday night's debate.