ICommand - Should I call CanExecute in Execute?

Question

Given that System.Windows.Input.ICommand as 2 primary methods:

interface ICommand {
  void Execute(object parameters);
  bool CanExecute(object parameters);
  ...
}

I expect CanExecute(...) to be called in the Command-supported frameworks before Execute(...) is called.

Internally to my Command Implementation, however, is there any reason to add the CanExecute(...) call inside my Execute(...) implementation?

e.g.:

public void Execute(object parameters){
  if(!CanExecute(parameters)) throw new ApplicationException("...");
  /** Execute implementation **/
}

This becomes relevant in my testing, as I may mock out some interfaces to support CanExecute, and have to do the same mocks when testing Execute.

Any design thoughts on this?