How to use session in a different thread?

Suppose that upon button click in my web form, a process will take 5 minutes to complete. So, I am trying to delegate the task to a different thread like so:
protected void btnSubmit_Click(object sender, EventArgs e)
{
      Thread t = new Thread(()=> DoTheTimeConsumingJob());
      t.Start();
}
And here is the method DoTheTimeConsumingJob:

private void DoTheTimeConsumingJob()
{
    ... ... 
    Session["funkie"] = myFunkieObject;
    ... ... 
} 
This will not work because the new thread knows nothing about Session.
So how would you make use of Session in a different thread in asp.net?  Thank you. 
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