Rep. Alexandria Ocasio-Cortez – the progressive firebrand from New York City – is definitively backing presumptive Democratic presidential nominee Joe Biden’s White House bid.

“In November, I’m going to be voting for Joe Biden. That’s what I’m going to be doing,” the freshman congresswoman said Wednesday night in an appearance with the Bronx-based rapper and actor Fat Joe.

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“I’ve been saying this whole time that we’ve got to support the Democratic nominee,” Ocasio-Cortez explained. “This is the time I’m saying it declarative like this.”

The congresswoman joined Fat Joe – whose real name is Joseph Antonio Cartagena – on his Instagram livestream.

Ocasio-Cortez – the highest-profile of the four freshman female progressive representatives known as ‘The Squad’ – was a top supporter and surrogate for populist Sen. Bernie Sanders' presidential campaign. The Vermont lawmaker – who was Biden’s last remaining rival for the Democratic presidential nomination – dropped out of the race and endorsed the former vice president earlier this month.

Since then, Biden's been reaching out as he tries to win over the progressive base of the party.

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Last week, in an interview on “The View,” Ocasio-Cortez said that “I think it’s really important that we rally behind our Democratic nominee in November.”

Before apparently warming a bit the last couple of weeks to Biden’s White House, Ocasio-Cortez was a vocal critic of some of Biden’s proposals.

Last year, she called Biden’s climate change plan “a dealbreaker.”

“There is no 'middle ground' w/ climate denial & delay,” the congresswoman tweeted.

Early this month, Ocasio-Cortez was skeptical of Biden’s announcement that he wants to lower the Medicare eligibility age to 60, which was seen as an olive branch to progressives as he works to unify the Democratic Party.

But the congresswoman said that Biden hadn’t gone far enough, adding that “dropping Medicare to 60 is not going to help millennials, is not going to help this electorate that Biden is struggling with.”