1.Reese Witherspoon shared this photo of herself (complete with that hairstyle every girl wore to prom from 1996–2001) taken at the premiere party for her film Freeway in 1996:
2.Inspired by Reese's #TBT, January Jones posted this modeling photo of herself in the late '90s, where she looked like the glam alt-baby of Courtney Love and D'arcy Wretzky:
3.Troye Sivan shared this video of himself being interviewed in 2007:
4.Heidi Klum posted this photo of herself feeding her dolls in the late '70s:
5.Jessie J shared this photo of herself alongside her little sister in the late '90s:
6.Christina Aguilera posted this video of herself singing Etta James' "Sunday Kind of Love" in 1988, and WOW:
7.Diana Ross shared this stunning photo of herself taken by Victor Skrebneski in 1975:
8.In honor of Robert Downey Jr.'s 55th birthday, Gwyneth Paltrow posted this photo of him giving a toast at her wedding in 2018:
9.David Bowie's official account shared these photos from when he (iconically) played Jareth in 1986's Labyrinth:
10.Elizabeth Taylor's official account shared these photos of her attending the Oscars in 1960 (where she was nominated for Best Actress for Suddenly Last Summer):
11.Paris Hilton jumped on the Tiger King obsession and posted this photo of herself and little sister Nicky Hilton dressed in cat print in the early '00s:
12.John Stamos posted this video of John Fogerty and Bruce Springsteen jamming out to Creedence Clearwater Revival songs at Fogerty's 50th birthday party in 1990:
13.Natalie Portman shared this photo of herself and Lily-Rose Depp taken in 2017:
14.And finally, Britney Spears gave us a double #TBT by posting these two photos of herself presenting at the 2002 Teen Choice Awards. Once with Verne Troyer...
15....and once with her little sister, Jamie Lynn Spears: