Prepare to feel old.

Some actors become inextricably linked to roles or other performers. And for audiences, it becomes a moment in time. Mark-Paul Gosselaar has done many things in his career, but when it comes down to it, he'll always be remembered as Zack from Saved by the Bell. And his foil on that show? Mr. Belding, memorably played by Dennis Haskins.

Well, this may be hard to believe, but Gosselaar is now older than Haskins was when the show premiered. Not even Slater has the muscle to help you wrap your head around that. They're hardly alone, though.

Let's hop in the way back machine and take a look above at some actors and actresses who are now older than their best-known co-stars were when they launched their signature projects.