Cameron Diaz has long been a fixture on best body lists, and now that the star is 40 she's only getting stronger. Diaz recently told Access Hollywood that she "loves getting older." Well, with that flawless physique, who wouldn't love it? Her secret to staying fit at 40 is a combination of Pilates, surfing and running to target different muscles. "My [butt] is definitely higher than it was when I was 20," says Diaz. "This is the thing that people don’t understand: Take care of your body [and it will] get better! It gets better as I get older." If you've got a milestone birthday approaching, change up your routine and add in a new workout, like boxing or hiking, for improved results.