use g_thread_new with a struct

use g_thread_new with a struct

I want to start a struct method in an own thread:
g_thread_new( "NewThread", mymethod , NULL)
The problem is, the program only compiles if I set the method to "static":
static gpointer mymethod(gpointer nrp) { puts(this->mystring) ; ... }
But if I set the method to "static" I cannot access the struct instance
variables like this->mystring.
Is there a way to use g_thread_new with class methods AND access instance
variables?