No, not the movies. If you love them, nothing personal. I just can't seem to say that word anymore without the thought of fan girls attached to it. Instead, I'm talking about the kind of twilight that I fan girl over. Those 15 minutes of light that lasts after the sun drops below the horizon. If you're lucky enought to live somewhere with mountains, that twilight time can last WAY longer since the mountains bring the horizon up a bit higher and the soft light lasts longer before the sun is finally gone. I shoot back light for the majority of a shoot until the twilight comes out to play. Once the sun drops out of site, I typically switch over to front light to take advantage of that gorgeous, soft, flattering light.
5D III + 35L / 5D III + 50L
Just like overcast days, twilight is a perfect time to have your subject looking to the sky for the gorgeous, soft light. When you do, keep in mind that it's still important to know which direction the light is coming from so you don't end up with light going up into their face instead of falling on it from the top. When in doubt, point their legs away from the sunset!