Memory occupied by reference to a variable in cpp [duplicate]

This question already has an answer here:

• How does a C++ reference look, memory-wise? 8 answers

Declaring pointer:

int a; int *x=&a;

x occupies 8 bytes of memory

Likewise if we declare a reference to a variable:

int a; int &x =a;

How much memory does the the reference to a occupy?