1. In celebration of the 10th anniversary of Victorious, Ariana Grande posted these wonderful behind-the-scenes photos taken throughout the show's run:
2. And she also posted these behind-the-scenes video clips:
3. In honor of Mariah Carey's 50th birthday, Britney Spears posted this photo of the two of them at a dinner party in 2017:
4. Britney also celebrated the 20th anniversary of her hit single "Oops!... I Did It Again" by posting this photo from the music video for it:
5. Also feeling the double #TBT pics this week was Janet Jackson, who shared this beautiful photo of herself from the early '00s:
6. As well as her headshot from the early '80s:
7. Tom Holland remembered when he was in Bali:
8. Ricky Martin shared these photos of himself, taken by Bruce Weber, in the late '00s:
9. Chrissy Teigen posted this photo of herself from 2010 in celebration of the 10th anniversary of her breast implants:
10. Kim Kardashian shared this photo of herself and her BFF Allison Statter in college in the early '00s:
11. Halle Berry posted this pic of herself in the late '90s:
12. Drew Barrymore shared this photo of herself visiting Kauai in 1993:
13. Natalie Portman posted this photo of herself dressed as a doctor in the early '80s and dedicated it to health care workers around the world:
14. Jackée Harry celebrated the 26th anniversary of the premiere of Sister, Sister by sharing this cast photo:
15. And finally, Joesph Gordon-Levitt reminisced about shooting 10 Things I Hate About You in celebration of the movie's 21st anniversary:
Today, March 31st, is the anniversary of '10 Things I Hate About You.' All of us were friends and spent so much time together that whole summer. Nothing but love for all the wonderful memories I had making that movie. ❤️