New York City will begin guaranteeing comprehensive health care to every single resident regardless of someone's ability to pay or immigration status, an unprecedented plan that will protect the more than half-a-million New Yorkers currently using the ER as a primary provider, Mayor Bill de Blasio said.

It's not health insurance, his spokesman clarified after the surprise announcement on MSNBC Tuesday morning.

"This is the city paying for direct comprehensive care (not just ERs) for people who can't afford it, or can't get comprehensive Medicaid — including 300,000 undocumented New Yorkers," spokesman Eric Phillips tweeted.

New Yorkers will be able to access the program through the city's website or simply by calling 311. There will be no tax hikes to fund it, the mayor said.