Mary-Kate & Ashley Olsen
Height of fame: They're still pretty famous, but the Olsen twins had way more fans in the '90s when they were babbling infants playing the same role on Full House. Michelle Tanner was a one-liner sensation ("You got it, dude!") and the Olsens personified cuteness on TV.
Now: They're separate people, let's make that clear, but the twins have stayed close. It helps they've been massively successful financially. They're well-known as fashion moguls, but the twins also own Dualstar, which produced all their content since the '90s. They're two of the wealthiest women in entertainment today.