PEOPLE Magazine 40th Anniversary

Look Who's Turning 40

From Leonardo DiCaprio and Victoria Beckham to Hello Kitty and Happy Days, see who's celebrating the milestone with PEOPLE

TIFFANI THIESSEN

She'll always be Kelly Kapowski to us – and that might be because Thiessen still has the same teen queen glow she did on Saved by the Bell. Her secret? The White Collar star drinks tons of water, uses sunscreen, and gets regular facials, she tells PEOPLE. After turning 40 in January, Thiessen says, "So far I'm doing okay. I'm feeling pretty good. The thing that makes me young and old is my kid. She can make me feel super, super young, and at the same time she can make me feel really old."