The "Shake It Off," singer captioned the picture “HAPPY BIRTHDAY AUSTIN!!!!! Thanks for 24 years of LOLs.”
Taylor and her bro were two of the cutest kids around back in the day, clearly already sharing some major laughs in the pic and it's totally adorable the two have managed to maintain such a strong bond over the years.
We're sure she was able to spend the day with her brother and give him one the best birthdays ever.
How cute were these two as kids? Tell us in the comments below!