Actress Cynthia Nixon, best known for her portrayal of Miranda Hobbes in HBO’s “Sex and the City,” announced Monday on Twitter that she’s running for governor of New York City.

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“I’m a proud public school graduate and a prouder public school parent,” Nixon said in a two-minute video announcing her candidacy. “I was given chances I just don’t see for most of New York’s kids today. Our leaders are letting us down.”

Her announcement sets up a race pitting an openly gay liberal activist against a two-term incumbent with a $30 million war chest and possible presidential ambitions.

Rumors have swirled for months that Nixon, 51, might throw her name in the hat against current Gov. Andrew Cuomo, according to Entertainment Weekly. In August, The Wall Street Journal reported that liberal activists were pushing for her to run based on her own history of liberal activism.

“She’s an out-of-the-box candidate with progressive credentials who would excite people,” Billy Easton, director of the public-education advocacy group Alliance for Quality Education, told the Journal in August.

The 51-year-old Manhattan mother of three is an ally of Democratic New York City Mayor Bill de Blasio, who frequently clashes with Cuomo on various issues.

The 60-year-old Cuomo was favored 66 percent to 19 percent over Nixon in a recent Siena College poll.

The Associated Press contributed to this report.