Whilst story mode is loaded up press
and scroll right using
to the 'Rockstar Editor' menu and press
to enter. Choose 'Director Mode' from here and accept the launch.
Click actors and pick any you wish though using an animal, your GTA online character or the Story Character 'Cris Fromage' will also unlock another achievement.
Once the mode loads the achievement will pop, here's a video using Cris Fromage