C++ programming

Hi all,
My question is, Is it legal to use 'this' pointer inside a constructor? for example

class Test
{
private
int var;
public
void Test(int); // constructor
};

Test *ptrToTest; // defined outside the class definition

void Test::Test(int) // constructor
{
var = int;
ptrToTest = this ; // is this legal to do?

}
Thank you all in advance for your help.

Anna