BY CELESTE KATZ

Talk show host and comedienne Chelsea Handler is keeping it classy -- NYCLASS-y, that is.

Handler has an open letter and petition up on the site of the animal rights group, urging Mayor Bloomberg to back the phase-out of the horse-drawn carriage.

"Dear Mayor Michael Bloomberg: You're a man who has money and I'm a woman who loves money so I wanted to let you know that I'm donating $15,000 to a cause you don't believe in -- yet," Handler writes.

She backs NYCLASS (that's New Yorkers for Clean, Livable and Safe Streets) in pushing to replace the buggy with "an eco-friendly 21st century horseless carriage" that will "promote tourism, save jobs and keep the horses out of harm's way."

Handler, who recently said she didn't even have time to star in her own show, adds: "If I didn't have a wildly successful career in television and entertainment, I'd be chomping at the bit to work full time on getting this car built. But since I've got a talk show, I'll write a check and do my part that way."

A bill to replace the carriages with green retro-style cars is on hold in the City Council.

Horse carriages are always a hot topic in the animal activism community, but probably no more so than when an animal gets injured or killed on the job. When a horse suddenly died in midtown in October, Bloomberg -- whose daughter is an equestrian -- said the cause would be investigated, but that it was no reason to take apart the entire industry, which he cited as a tourist draw.

"The horses are well taken care of and we support the industry in NYC," Bloomberg spokeswoman Samantha Levine reiterated this afternoon when I asked about Handler's appeal.

Among other headliners who support ridding the city of hansom cabs: Academy Award winner Anjelica Huston, Lea Michele of "Glee" and former "Baywatch" babe Pamela Anderson.