1.Selena Gomez shared this photo of her (doppelgänger) mom holding her as a baby.
2.Green Day took it back to the early '90s with their photo.
3.Jennifer Love Hewitt celebrated the 20th anniversary of her classic horror movie, I Know What You Did Last Summer, by posting the poster.
4.Nico Tortorella shared this teenage photo of himself cuddling a puppy.
5.Nick Kroll posted this tween photo of himself enjoying a burger and fries.
6.Janet Jackson celebrated the 31st anniversary release of the her hit song "Control" by sharing a pic of the Control album.
7.Orlando Bloom posted this super cute childhood photo of himself decked out in velour.
8.Naomi Campbell shared this photo from her early modeling days.
9.Christina Aguilera honored Spirit Day (a day that brings attention to the bullying suffered by LGBTQ kids) by posting this photo of herself in the purple outfit she wore in the music video for "Can't Hold Us Down."
10.Dan Levy posted his class photo of himself (with a purple filter) in honor of Spirit Day.
11.And finally, Michelle Trachtenberg got into the Halloween spirit by posting a photo of herself dressed as Poison Ivy in 1997.