Source Environment variables for state.tf

Terraform
1

Is there a way to use TF_VAR in the definition of state.tf?

state.tf

terraform {
  backend "s3" {
    bucket = "example"
    key    = "example"
    region = "us-east-1"
  }
}

basically source the bucket and key vars via TF_VAR?

I am trying to implement this for CI/CD automation and use. single .env file to source