In the very first TikTok posted to Young Sheldon's official TikTok account, Iain Armitage and Jim Parsons, who played Sheldon on 'Young Sheldon' and 'The Big Bang Theory' respectively, morph into each other and joke that they used an aging filter.
https://people.com/iain-armitage-transforms-into-jim-parsons-in-young-s…