Mere hours after Prince William and Kate Middleton left St. Mary’s Hospital with their newborn son on Monday, the Obamas were already making plans to meet the third royal baby. Following the still unnamed prince’s introduction to the world outside the hospital’s private Lindo Wing, Michelle Obama took to Twitter to congratulate the Duke and Duchess of Cambridge on the newest addition to their family and lay the groundwork for a future visit with the young royal. “Barack and I are thrilled to congratulate The Duke and Duchess of Cambridge on their newest arrival,” she wrote.