Access Master Page public method from user control/class/page

I am to access a method on my master page. I have an error label which I want to update based on error messages I get from my site.

public string ErrorText
{
    get { return this.infoLabel.Text; }
    set { this.infoLabel.Text = value; }
}

How can I access this from my user control or classes that I set up?