How To Access The Session From A Different Project Within The Solution

I have 2 projects in my solution.

MVC Web application
Class library

The MVC Web application references the class library.

The class library contains a class that extends the default ASP.Net Controller.

I'm putting a variable in session in the application's Global.asax.

protected void Session_Start(object sender, EventArgs args)
{
HttpContext.Current.Session["DomainName"] = Request.Url.Host;
}

In the class library I'm trying to get the value from the HttpContext.Session, but HttpContext.Session keeps coming up null.

[code]...

HttpContext.Current.Session doesn't seem to be an option in controllers.