cannot bind to a value of unrelated type when using a class constructor

I have a class like:

class A {

   //constructor
   A(const unsigned long long x)
   {
      //some code here


    }
}

I also have a templated function like

  template<typename T> fcn(T & dest, unsigned long long x)
  {
    T data(x);
    dest = data;
  }

When I try to use this function by doing something like:

A data;
unsigned long long x = 11;
fcn<A>(data, x);

I get an error message of the form:

error: non-const lvalue reference to type 'A' cannot bind to a value of unrelated type 'const unsigned long long'

It seems that the compiler is trying to assign x to data, instead of invoking the corresponding constructor of A. How can I fix this in C++11? What am I doing wrong? Thanks