John Stamos won Throwback Thursday by sharing a 1989 behind-the-scenes video from his Full House days – with the Olsen twins, then just 4, posing for the camera and saying "Jesse!" (Maybe they didn't know him as John back then.)
Though Mary-Kate and Ashley Olsen, who portrayed Michelle Tanner on Full House from 1987–95, did not return for spinoff Fuller House, executive producer Bob Boyett explained why in an earlier interview with PEOPLE.
"Ashley said, 'I have not been in front of a camera since I was 17, and I don't feel comfortable acting,' " said Boyett of the 29-year-old sisters. "Mary-Kate said, It would have to be me because Ash doesn't want to do it. But the timing is so bad for us."
The pair are also busy running their fashion empire in New York – with the premiere of Fuller House joking that was why their character was not present.