Dan Gerstein, a spokesman for Lieberman's campaign, says the fundraiser will be held on Nov. 1 and will be co-chaired by another Republican, former New York Sen. Alfonse D'Amato, and former Democratic Mayor Ed Koch.
Lieberman, a three-term incumbent lost the Democratic primary to Greenwich businessman Ned Lamont in August and is running for re-election as a third-party candidate, a move that has alienated many Democrats. Polls of likely voters show Lieberman leading Lamont, with Republican Alan Schlesinger trailing badly.
Lieberman hopes to attract unaffiliated and Republican voters. State and national Democratic leaders are backing Lamont.
Bloomberg spokesman Stu Loeser said the mayor is looking forward to helping Lieberman. Loeser says that Bloomberg "thinks the world of Sen. Lieberman, because he speaks his mind and does what he thinks is right."
Lamont spokeswoman Liz Dupont-Diehl says the fundraiser represents the kind of politics Lamont is trying to change.