Toni Preckwinkle just added $1 million to her mayoral campaign treasure chest.

The cash infusion Monday came from the Service Employees International Union state council.

In 2015, the group — the political arm of SEIU in Illinois, comprised of SEIU Local 1, SEIU Local 73, and Healthcare Illinois Indiana — backed Jesus “Chuy” Garcia with $3 million mainly in the form of direct contributions, in kind contributions and television ads in an unsuccessful bid to unseat Mayor Rahm Emanuel.

SEIU spokeswoman Izabela Miltko-Ivkovich wouldn’t say how much money they were prepared to spend on Preckwinkle when reached via email Monday afternoon.

But with the Feb. 26 mayoral election more than two months away, she did say the labor group “will make sure Toni Preckwinkle has the resources she needs to compete and win.”

SEIU represents 80,000 working people, including home care and child care providers, security officers, janitors, as well as public employees, medical professionals, first responders and social service workers in Chicago — and more than 150,000 workers statewide.

It’s not the first time SEIU has backed Preckwinkle.

Prior to Monday’s donation, records show that Preckwinkle received $1.1 million in cash and in kind contributions from SEIU labor unions over the years. The majority of those donations were made in 2010 to help her defeat then Cook County Board President Todd Stroger.

Both SEIU Healthcare and Local 73 announced their endorsement of Preckwinkle last week.

SEIU Local 1 backed Preckwinkle in September and has already put $100,000 in direct cash and another $100,000 in kind contributions into her mayoral campaign, Miltko-Ivkovich said.

SEIU Local 1 is part of a group of unions that now owns the Chicago Sun-Times.