How to use a static color for Chart.js bar chart's legend, when using an array of background colors

Question

I have a Chart.js bar chart that has its backgroundColor set as an array.

Example:

{
  type: 'bar',
  label: "...",
  data: [...],
  borderColor: '...',
  backgroundColor: ["var_color1", "var_color2", ..., "var_color3"],
  yAxisID: 'y',
}

The legend above the chart always takes the first color in the backgroundColor array, but I want it to be a static color that I can set manually.

For instance, to always be green here and not the first color in the array that is orange:

Could anyone please provide a solution for this case?
Please note that I am using react-chartjs-2.