Sex and the City actress and activist Cynthia Nixon is running for governor of New York, staging a high-profile Democratic primary challenge against two-term incumbent Andrew Cuomo.

Nixon’s announcement has been teased for months, but she made it official on Monday with the release of her first campaign ad.

Nixon, 51, hasn’t previously held public office, and while she’s probably still best known for playing lawyer “Miranda Hobbes” on the HBO series Sex and the City, she has been a longtime activist on progressive issues. She’s pushed for LGBT rights, and she’s also a vocal education advocate, calling for increased funding for public schools. She is also a prominent supporter of New York City Mayor Bill de Blasio — who just so happens to have a public feud with Cuomo — and Nixon’s wife worked for de Blasio’s administration in the Department of Education before recently stepping down.

Nixon is a potentially history-making candidate and if elected, she’d be New York’s first woman governor, and the first openly gay governor, not just of New York, but of any state.

Nixon officially jumped into the governor’s race on Monday. Though she didn’t mention the governor by name in her first campaign ad, she called out the state’s “leaders for failing us,” saying New York was the most “unequal state” in the country.