It was a weekend of special deliveries for Kourtney Kardashian and Sienna Miller. Both young women welcomed their new babies, half a world away from each other. In Los Angeles, it was a girl for the 33-year-old E! reality star. Kardashian and long-time boyfriend Scott Disick are celebrating the arrival of Penelope Scotland Disick. Little Penelope is the second child for the couple, who are the proud parents of 2-year-old Mason. An insider tells Us Magazine, "The entire Kardashian/Jenner clan was at the hospital and everyone was super excited!" Sister Kim, who is currently dating rapper Kanye West, couldn't say enough about the new addition. She took to her blog to dish on her new niece, writing, "Welcome to the world, Penelope Scotland Disick! Kourtney gave birth to a beautiful baby daughter on Sunday and the whole family is so thrilled to finally meet her!" Kim didn't stop there -- she announced her intentions to shower Penelope with love, affection and plenty of goodies. The 31-year-old added, "She is absolutely perfect! I am so excited to be an aunt again and can't wait to spoil little Penelope. I know Mason is going to be the best big brother in the whole world. Congratulations Kourtney and Scott. Xo." In London, Sienna Miller also gave birth to a baby girl. The baby, whose name hasn't been released yet, is the first child for Miller and fiance Tom Sturridge, who isn't Jude Law. Miller and the actor have been together for more than a year and got engaged in February.