Constance Zimmer, Jimmy Kimmel, and Other Stars Look Unrecognizable in #ThrowbackThursday Photos

Throwback Thursday, as we've demonstrated before, is a pretty amazing thing. We get to remember our favorite moments with stars, get some insight on some childhoods, and sometimes, see a whole new side of someone. These photos? They're more of the latter.

Hugh Hefner, Paris Hilton, Jessie J, and more used to look a lot different ;— at least for the 1/60 of a second it took to snap these pictures! Click here to see some stars looking a little different than usual.