Its Beyoncés twins birthday, but the proud mother is the one sensation lucky today.The 39-year-old music super star posted a heartfelt message to her individual site on Sunday, June 13 to mark Rumi and Sirs 4th birthday.” Its not a huge surprise that Bey and Jay have yet to publish images of Rumi and Sir on their special day, as the parents tend to be quite personal when it comes to sharing glimpses of the little ones.On March 31, the “Formation” singer offered an uncommon look at her twins throughout a day out in Malibu, Calif, with her 3 children, where they took pleasure in a meal at popular Japanese dining establishment Nobu and played in the ocean. Rumi and Sirs faces werent noticeable in the images.Beyoncés Twins: Inside Rumi and Sir Carters Lavish WorldOne shot revealed Beyoncé reaching out to Sir, who was using a white t-shirt and beige shorts with his hair in a small bun.