(The Center Square) – Andrew Cuomo’s independent bid for mayor of New York City is formally endorsed by billionaire former mayor Michael Bloomberg, a move he hopes will slow the momentum of Democratic socialist and frontrunner Zohran Mamdani with just days until the election.

Bloomberg, contributing more than $8 million to a super PAC supporting Cuomo’s candidacy, formally threw his support behind the former governor's campaign Wednesday night in a social media post that lauded Cuomo's years of political experience over the newcomer.

Voters decide on Tuesday. Early voting ends Sunday.

"Being mayor of New York City is the second toughest job in America, and the next mayor will face immense challenges," Bloomberg wrote. "Andrew Cuomo has the experience and toughness to stand up for New Yorkers and get things done. I hope you will join me in supporting him."

Bloomberg, a Democrat and former Republican who served three terms as mayor, first endorsed Cuomo two weeks before New York City’s June 24 primary. Earlier this week, Bloomberg pumped $1.5 million into a super PAC supporting Cuomo.

His latest endorsement comes less than a week until Election Day and after hundreds of thousands of New Yorkers already casted their ballots during a weeklong early voting period that got underway Saturday.

Cuomo welcomed Bloomberg's formal nod to his candidacy, saying in a statement late Wednesday that it "was an honor to have the support of a mayor who knows firsthand what it takes to run this city."

Other top New York Democrats, including Gov. Kathy Hochul and House Minority Leader Hakeem Jeffries, have thrown their support behind Mamdani, a Queens assemblyman who won the Democratic party's nomination after defeating Cuomo in the June primary.

U.S. Senate Minority Leader Chuck Schumer, emerging throughout the month at the center of a federal government shutdown, has not made an endorsement.

A Quinnipiac University poll released Wednesday found Mamdani maintaining a double-digit lead but showed the race has tightened since incumbent Mayor Eric Adams announced plans not to seek another term. Pollsters found 43% of likely voters supported Mamdani, with 33% for Cuomo and 14% for Republican nominee Curtis Sliwa.

Sliwa, a perennial mayoral candidate and founder of the Guardian Angels, has faced pressure to drop out of the race to clear the way for a one-on-one race between Cuomo and Mamdani. He has refused to bow out.