1. In honor of Reese Witherspoon's 42nd birthday, Sarah Michelle Gellar posted this photo of the two of them from their iconic 1999 film, Cruel Intentions, vs. today.
2. John Stamos shared his adorable baby photo.
3. In honor of Rob Kardashian's 31st birthday, Kim posted this photo of the two of them from a New Year's past.
4. Keeping the birthday-theme going was Rashida Jones, who in honor of her big sister Kidada Jones' bday, posted this way too cute photo of the two of them in the late '70s.
5. Miss Piggy shared this fab photo of herself in the '70s.
6. Dolly Parton posted this photo of herself performing in 1974.
7. Michelle Trachtenberg shared this photo of herself on the red carpet of her 1999 film, Inspector Gadget.
8. Paul McCartney posted this photo of himself on the London Tube in 1969.
On the Bakerloo Line, London. Photo by Linda McCartney #ThrowbackThursday #TBT
9. Trixie Mattel celebrated winning RuPaul's Drag Race All Stars 3 by posting this photo of herself at 5 years old.
10. Laura Prepon posted this sweet childhood photo of herself.
Looking ahead to some nicer weather in NY! Spring is out there somewhere… #tbt #ThrowbackThursday