In the world of private Hollywood couples, Macaulay Culkin and Brenda Song stand out for their ability to keep their personal life just that — personal. Still, when these two sneak out for a rare date night or share a snippet of their life together, it’s like spotting a unicorn in the wild. That’s exactly what happened when Culkin turned to Instagram to celebrate his fianceé’s 36th birthday, giving fans a glimpse into their life together with a post that was equal parts sweet and silly.