"Ok here's pic of me geeking out on my YSL campaign. I was in Paris for fashion week and look what I stumbled upon!" That's Jessica Chastain, who shared on Facebook her admittedly endearing giddiness about the fact that her face is currently overlooking one of the most famous rivers in the world. "It was as tall as a building," she continued. " It was super embarrassing but I had to jump out of my car and seize the moment. I mean, how many times does a girl get a billboard over the Seine River!?!" Indeed.