Switch statement and object implicit int conversion

In C++, is it legal / correct to use switch statement directly on an object which has an implicit conversion to int ? Instead of using a method returning the object tag.

class Action
{
  public:
    enum EType { action1, action2, action3};
    operator int() const { return mType; }
  private:
    EType mType;
  /* ... */
}

int main()
{
    Action a = /* ... */
    switch(a)
    {
    case Action::EType::action1:
        /* ... */
        break;
    case Action::EType::action2:
    /* ... */
    }
}