For those who aren't filter-savvy, to participate in Throwback Thursday Instagram users post old photos of themselves with the hashtag #TBT on – you guessed it – Thursday.
Out of the countless pictures already posted to the social network, 127 million shots are branded with #TBT, making it one of the most popular hashtags of 2013.
Luckily for us, celebrities love to revisit memories and indulge in a little #TBT. Millions of old photos were shared in 2013, but these celeb shots were the most popular Throwback Thursday Instagram posts of the year.
2. Beyoncé, Again
1. One Direction's Niall Horan
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