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California Gov. Gavin Newsom named Democratic strategist Laphonza Butler as Sen. Dianne Feinstein's replacement in the U.S. Senate after the longtime Democrat senator died last week at the age of 90, Fox News confirmed late Sunday night.

Butler will finish out the remainder of Feinstein's term in Washington, D.C., ahead of the 2024 election. In a statement, the governor described Butler as an "advocate for women and girls, a second-generation fighter for working people, and a trusted adviser to Vice President Harris."

"As we mourn the enormous loss of Senator Feinstein, the very freedoms she fought for — reproductive freedom, equal protection, and safety from gun violence — have never been under greater assault," Newsom added. "Laphonza will carry the baton left by Senator Feinstein, continue to break glass ceilings, and fight for all Californians in Washington D.C."

Butler, president of EMILY's List and a former adviser to Vice President Kamala Harris' presidential campaign, will be the only Black woman serving in the U.S. Senate and the first openly LGBTQ+ lawmaker to represent the Golden State in the upper chamber.

ALL EYES ON CALIFORNIA GOV. NEWSOM TO QUICKLY NAME TEMPORARY SENATE REPLACEMENT FOR FEINSTEIN

Laphonza Butler

California Gov. Gavin Newsom announced Sunday Democratic strategist Laphonza Butler will assume Sen. Dianne Feinstein's seat in the U.S. Senate. (AP)

EMILY’s List is a political organization that works to elect Democratic women who support abortion access. Butler's EMILY's List biography had listed her residence as Silver Spring, Maryland, earlier Sunday evening, but it was removed from the profile shortly after it was announced she would be appointed to the position. An FEC filing from Aug. 31 also showed a Maryland address.

Newsom previously vowed to place a Black woman in any Senate seat that became vacant – a promise that was criticized by U.S. Rep. Barbara Lee, D-Calif., who said the Democrat governor's pledge was "insulting" to Black women since the appointment would be temporary ahead of the primary.

"The idea that a Black woman should be appointed only as a caretaker to simply check a box is insulting to countless Black women across this country who have carried the Democratic Party to victory election after election," Lee, who is already running for Feinstein's seat, previously said in a statement.

Newsom has said he would not choose someone already running for the seat because he wants to avoid giving a candidate an unfair edge in the election, which will be held in 2024. Democratic U.S. Reps. Katie Porter and Adam Schiff, both of whom represent California in Congress, have also launched campaigns to replace Feinstein.

LONGTIME SEN. DIANNE FEINSTEIN PASSES AT AGE 90

Feinstein in a wheelchair

Sen. Dianne Feinstein died on Thursday at the age of 90 after battling a series of illnesses. (Anna Moneymaker/Getty Images)

Newsom's spokesman Anthony York said the governor did not ask Butler to commit to staying out of the Senate race.

Feinstein died on Thursday after battling a series of illnesses. She was the oldest member of Congress and the longest-serving woman in the Senate. The senator said in February she would not seek re-election next year.

Butler called Feinstein a "legendary figure for women in politics and around the country" in a statement posted after the senator's death last week.

While Butler has never been elected to office, she has been involved in California politics for years. She served as a senior adviser to Harris's 2020 presidential campaign while at the same time working at a political firm with strategists who have worked for Newsom and other prominent state Democrats. She also has two decades of experience in the labor movement, including formerly serving as a labor leader with SEIU 2015.

California Gov. Gavin Newsom

Gov. Gavin Newsom had previously vowed to select a Black woman to replace any vacant Senate seat since there are no Black female senators currently serving in the chamber. (Justin Sullivan/Getty Images)

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Butler's nomination marks the second time Newsom has selected a U.S. senator since 2021, when he chose then-California Secretary of State Alex Padilla to replace Harris after she was elected vice president.

Feinstein's seat is expected to remain in Democratic control following the 2024 election, as the party has not lost a statewide election in the deep blue state since 2006.

The Associated Press contributed to this report.