Stefani is the global ambassador for the high street beauty brand, so it only makes sense why the fiery colour would catch Shelton's eye so often. After all, she's practically the patron saint of red lipstick. And while we're pretty sure most significant others would never notice the brand of lip colour we were wearing, it's nice to know that Shelton pays attention to details — even if he can't quite tell the difference between the Cherries in the Snow and Spicy Cinnamon shades.