Taylor Swift's hot younger brother [2], Austin Swift, rang in his 24th birthday on Friday, and Taylor marked the special occasion with the ultimate throwback photo. The singer, who recently celebrated her one-year anniversary with boyfriend Calvin Harris [3], shared an adorable childhood snap of herself and Austin cracking up, writing, "HAPPY BIRTHDAY AUSTIN!!!!! Thanks for 24 years of LOLs. @austinkingsleyswift." Of course, this isn't the first time Taylor's taken a trip down memory lane. Back in September, she melted hearts everywhere when she posted a flashback shot of herself and her brother on a tractor [4]. See the precious snap above now, and then check out what Austin recently said about Taylor's feud [5] with Kanye West.