Template specialization of particular members?

Is it possible to specialize particular members of a template class? Something like:

template <typename T,bool B>
struct X
{
    void Specialized();
};

template <typename T>
void X<T,true>::Specialized()
{
    ...
}

template <typename T>
void X<T,false>::Specialized()
{
    ...
}

Ofcourse, this code isn't valid.