Mayor-elect Zohran Mamdani on Wednesday responded to billionaire Bill Ackman’s olive branch in the wake of his historic election win — saying the Big Apple’s business bigwigs needed to work alongside him now.

The hedge fund titan, who vocally opposed Mamdani during the campaign, offered up his congratulations soon after the Democratic socialist declared victory over former Gov. Andrew Cuomo.

“Congrats on the win. Now you have a big responsibility. If I can help NYC, just let me know what I can do,” Ackman posted on X late Tuesday.

Initially, Ackman endorsed Mayor Eric Adams early on before making a dramatic about-face to throw his support behind Cuomo, who ran as an independent, just weeks ahead of the election.

“I appreciated his words,” Mamdani told “Good Morning America” early Wednesday when asked about Ackman’s offer to help.

“I think what I find is that there is a needed commitment from leaders of the city to speak and work with anyone who is committed to lowering the cost of living in the city — and that’s something that I will fulfill,” he added.

When he endorsed Cuomo’s now-failed election bid, Ackman had argued the ex-governor had the “relevant experience and skills necessary” to improve the city.

“There is a lot that needs to be improved in New York City. @andrewcuomo is an experienced leader that cares deeply about our city who has the relevant experience and skills necessary to lead and greatly improve NYC,” Ackman said at the time.

“Andrew had major accomplishments as our governor. He also made some mistakes. I am a huge believer in backing leaders who have learned from their mistakes and have something to prove.”