The Duke and Duchess of Sussex are celebrating their son Archie’s second birthday Thursday.The royal family has been wishing the toddler a happy birthday across social media, with the official Royal Family Instagram account sharing a sweet photo of him with his parents Prince Harry and Meghan at Windsor Castle in 2019.Other royal family members also celebrated the day, including Prince Charles and the Duke and Duchess of Cambridge, who shared memories from Archie's Christening in July 2019.Archie Harrison Mountbatten-Windsor was born at 5:26 a.m. on May 6, 2019, at the Portland Hospital in London. Days before Archie's second birthday, Meghan revealed that she would publish a children's book that's inspired by her son and her husband, Prince Harry. "The Bench" will be an illustrated story told through a mother's eyes, and will look at the "special bond between father and son." It was first written as a poem by Meghan for Harry to mark Father's Day in 2019. "Evoking a deep sense of warmth, connection, and compassion, 'The Bench' gives readers a window into shared and enduring moments between a diverse group of fathers and sons - moments of peace and reflection, trust and belief, discovery and learning, and lasting comfort," a statement from the book's publisher read.Earlier this year, the Sussexes revealed that they are expecting their second child, a girl. Harry and Meghan first announced that they were expecting again on Valentine's Day. At the time, the couple released a black-and-white photo of themselves together taken remotely by their longtime friend, photographer Misan Harriman.