Hide GUI label on press

Hi, I am using the GUI.Button() function to display a button on the screen and i wanted to know how i could make the button disappear once it was clicked on it.I know the bsic logic is to have an if condition and then enter the code, i wanted to know what that code would be.Thanks

in C#:

bool buttVisible = true;

void OnGui() 
{
    if (buttVisible) {
        if (GUI.Button( "....." )) {
            buttVisible = false; 
            ....
        }
    }
}