How to manage std::list elements as references?

I have the following code:

struct Foo {
    int var1;
    int var2;


    friend std::ostream& operator<<(std::ostream& os, const Foo& s){
        return os << "[Foo] " << s.var1 << "," <<  s.var2 ;
    }
};

int main() {
    Foo foo;
    foo.var1 = 1;
    foo.var2 = 2;
    std::list<Foo> list;
    list.push_back(foo);

    Foo &foo2 = list.front();
    foo2.var2 = 5;

    std::cout << "foo (" << &foo << "): " << foo << std::endl;
    std::cout << "foo2 (foo from list) (" << &list.front() << "): " << foo2 << std::endl;
}

I want both foo and foo2 to reference the same object. So when I assign 5 to foo2.var2, I would want to modify foo.var2 as well. Yet, as we can see in the following output this is not happening:

foo (0x7fffffffe140): [Foo] 1,2
foo2 (foo from list) (0x61ac30): [Foo] 1,5 

What would be the correct way to do that?