1. Ariana Grande shared this cute photo of herself from the early '00s:
2. Naomi Campbell remembered Whitney Houston on what would've been her 56th birthday by posting this photo of the two of them in the early '00s:
3. Tan France shared this photo of himself from 2006, where he had more questionable style:
4. Justin Bieber posted this photo of himself in elementary school in the early '00s:
5. Eva Mendes shared this photo of herself and her sisters in the late '80s:
6. Salma Hayek posted this video Cole Sprouse sent her daughter, Valentina, during this year's San Diego Comic-Con:
7. Celebrity photographer Terry O'Neill shared this photo he took of Sharon Tate in the late '60s:
8. Dolly Parton posted this photo of herself and Carol Burnett rehearsing for their 1979 TV special, Dolly and Carol in Nashville:
9. Troye Sivan shared this photo taken on the set of his music video for "Bloom":
10. Michelle Pfeiffer posted this photo of herself from the late '80s:
11. Kylie Minogue shared this photo taken during her KylieFever2002 tour:
12. Idris Elba posted this video clip from when he DJ'd in Ibiza last year:
13. Rob Lowe shared this photo of himself from the '70s:
14. Natalie Portman posted this photo of herself from the late '90s:
15. Mariah Carey was in a summer mood and shared these stunning photos of herself at the beach in 1997:
16. Kyle MacLachlan remembered his role as Cliff Vandercave in 1994's The Flintstones:
Nothing says ‘villain-with-style’ more than a suede double-breasted wrap by Karl Lagerfieldstone #TheFlintstones #TBT
17. Sofía Vergara shared this hot pic of herself from the '90s:
18. Paris Hilton posted this video clip of herself and her sister Nicky hitting up a club in 2000:
Back when we were teens hitting up the clubs with our fake ID's. ⚡️👯♀️⚡️ #TBT