Former State Rep. Marie St. Fleur is set to formally endorse Andrea Campbell’s candidacy for Mayor on Tuesday afternoon.

“Andrea Campbell is exactly the kind of leader Boston needs right now,” St. Fleur said in a statement. “She is informed by the painful losses and inequities she experienced growing up in Boston and driven by her understanding and knowledge of the opportunities that Boston holds for all people. These experiences allow her to see, hear, connect to, and fight for all people,” the former Fifth Suffolk district Rep. said in a statement released by Campbell’s campaign.

A longtime supporter of Campbell, St. Fleur first backed her back in 2015 when she challenged longtime incumbent City Councillor Charles Yancey for the District 4 seat.

“I am deeply humbled and proud to have Marie’s support in this race,” Councillor Campbell said. “Marie’s leadership in our city has always been about bringing people together across demographics and industries to advance equity and opportunity for all, and that’s exactly what this campaign is about. I’m proud that our campaign continues to build a diverse coalition of support in every neighborhood.”

St. Fleur, a Dorchester resident who represented the Fifth Suffolk district, has frequently used her Twitter account in recent weeks to support “#Team Andrea” and encourage her followers to sign Campbell’s nomination papers. She donated $1,000 to Campbell’s campaign in 2021 according to filings with the Office of Campaign and Political Finance, helping to push Campbell’s campaign war chest past $1 million as of May 3.

Other prominent Campbell backers include: Former First Lady Diane Patrick, former Suffolk County Sheriff and Secretary of Public Safety Andrea Cabral, Cambridge Mayor Sumbul Siddiqui, Governor’s Councilor Eileen Duff, State Representative Liz Malia, former State Representative Marty Walz, Bill Walczak, Diana Hwang, Dr. Atyia Martin, John Borders IV and Makeeba McCreary.

Campbell is one of five candidates who has officially secured enough signatures to qualify for the September primary as of Monday, according to the city’s elections department. Others include Acting Mayor Kim Janey, Councillors Michelle Wu and Annissa Essaibi George, and John Barros. State Rep. Jon Santiago, who is also running, has not yet been certified by election officials.