Mayoral candidate Ray McGuire’s long-shot bid to run City Hall is getting another big endorsement boost, this time in Queens, where he’s reeling in the support of the borough’s Democratic Party chairman, Rep. Gregory Meeks, The Post has learned.

Meeks is expected to announce his backing of McGuire, a former Citigroup executive, in the coming days, Queens Democratic Party insiders and campaign sources said.

Another prominent Queens Democrat, state Sen. Leroy Comrie, also just pledged his support to McGuire.

Earlier this week, hip-hop icons Jay-Z, Nas and Diddy gave their endorsements to McGuire on a Zoom call with the candidate to discuss his “inclusive comeback” plan for the city.

The backing of McGuire is a setback for fellow mayoral candidate Eric Adams, the Brooklyn borough president.

Meeks and Comrie represent predominantly black, working-class and middle-class neighborhoods in south Queens

Adams, who was raised in Jamaica, Queens, and attended schools in the borough, and McGuire are competing fiercely for the allegiance of residents in the same south Queens neighborhoods, which account for up to 40 percent of the borough’s Democratic primary vote, sources said.

The McGuire campaign declined comment. Meeks had no immediate comment.

Comrie declined comment Friday.

But last week Comrie pledged his support to McGuire during a virtual appearance with the candidate and Joseph Ward Simmons, the rapper known as Run, Rev. Run and founding member of hip-hop pioneers Run-D.M.C.

“From the time we met, we clicked,” Comrie said.

“I’ve been impressed with his desire to make a difference in people’s lives … He wants to be the mayoral of New York City so we all rise up.”

Comrie said he liked McGuire’s COVID economic recovery plan for small businesses — including waiving payment of the city portion of sales tax receipts for one year and providing subsidies to bring 50,000 jobs.

McGuire last month also won the endorsement of veteran Assemblywoman Vivian Cook, who represents the south Jamaica area where Adams grew up. She also is closely aligned with Meeks.

Adams has the backing of Queens Assemblywoman Jenifer Rajkumar and Council members Daneek Miller and Francisco Moya.

Other candidates also are hunting for votes in the city’s second-most populous borough.

Maya Wiley, who served as Mayor Bill de Blasio’s chief lawyer, scored the support of Assemblyman Khaleel Anderson, who represents the Rockaways and southeast Queens. She also has the backing of Sen. Michael Gianaris, who represents more liberal precincts of Astoria and Long Island City in western Queens.

Andrew Yang has been stumping hard in central Queens, which includes the Asian neighborhoods of greater Flushing and communities with sizable blocs of Jewish voters — Kew Gardens, Kew Gardens Hills, Forest Hills and Rego Park. Assemblymen Dan Rosenthal and Ron Kim have endorsed him.