Is it possible to have an rvalue reference as pimpl class in C++

Hey i want to create a class with a Pimpl (Private implemenation) and normal you would so:

class A
{
private:
  class B;
  B* _pimpl = nullptr;
}

and the i would define it in the cpp file. But i have to use dynamic allocation. Would it be possible to use a rvalue reference:

class A
{
public:
  A(); //Constructor to init rvalue reference
private:
  class B;
  B&& _pimpl;
}

And then in cpp file:

class A::B
{
public:
   int C = 3u;
}

//and then the constructor of A:

A::A() : _pimpl(B()) { } //now we should have a fresh b pimpl?

Im currenty on holidays and i only have my c++ book and when i read about rvalue&&s i tought it might work? What do you guys think?