Calling functions on the default form

Question

Hi, I'm sure this is a simple question but I can't for the life of me remember how to do it! Say I have my main form of type Form1, and from that form I create another form of type Form2, how do I call public functions in Form1 from Form2? The problem is that I don't know what the instance of Form1 is called since it's created when the application starts. Normally if I create another form I set the name, for example: Form2 foo = new Form2(); foo.publicFunction(bar); However with this scenario as I say I don't know how to refer to the default form! Many thanks, Ian Atkinson