Meghan Markle is marking International Day of the Girl by honoring the special little one in her life: 4-year-old daughter Princess Lilibet. "To all the girls - this world is yours," Meghan, 44, wrote via Instagram on Saturday, October 11. "Do everything you can to protect your rights, use your voice, support each other. We will do the same for you. It's your right and our responsibility." She added, "Go get 'em girl! 🏃♀️ Happy International Day of the Girl." Alongside her impactful caption, Meghan also shared a handful of rare images of her and husband Prince Harry's daughter.