We can't find a speck of hyperpigmentation on Paltrow's complexion, and her skin is incredibly smooth. Get it for yourself with a laser. "In your late 30s, if you have textural issues such as enlarged pores and sun damage, you can start on the Pearl laser and IPL," suggests Somerville.

The secret behind Witherspoon's healthy flush may have something to do with her daily jogs, during which papparazzi love to snap photos. "Late nights, smoking, excessive alcohol, unhealthy food, lack of exercise—all of this will take a huge toll on your skin now," warns Somerville. But don't fret: "It’s not too late to make changes, both in your lifestyle and your skin."

Besides her occasional weakness for Mexican food, Aniston's diet consists of lean fish and vegetables. And it's no surprise. "Exercise and a good diet are absolutely the fountains of youth at this age," says Somerville. "I’m a big believer in supplementing with vitamins, minerals, and omega-3 fatty acids now."

Last year, Kidman admitted to using Botox, but added that she wasn't happy with the results. Luckily, there's a whole range of treatments—from lights to lasers to other injectable fillers—that are more beneficial to women in their 40s than at any other age, says Somerville.

"Menopause is the defining occurrance in your fifties," informs Somerville. "Estrogen and progesterone levels drop like a stone, which results in you making less and less collagen and elastin." If you're not blessed with naturally-defined cheekbones à la Julianne Moore, plump up with injectable fillers like Juvederm, Radiesse, and Cosmoplast, which will fill out those areas that look gaunt and hollow. 

For women in their fifties, "subcutaneous fat degenerates and your muscles become more lax, causing sagging," explains Somerville. She's a fan of the Titan for tightening and lifting, so skin is firm but not bounce-a-quarter-off-it taut. Madonna's is smooth without looking nipped-and-tucked.

Sun spots? Uneven skin tone? Stone will have none of that. Replicate her perfect tone with a resurfacing laser treatement. At this age, says Somerville, you're the best candidate for Titan, which restores smooth texture to skin and removes hyperpigmentation.

Keaton has been rocking a shoulder-length haircut for years, and according to Somerville, that may be part of why she gives off an energetic, younger-than-her-years vibe. "Pay attention to your hair, teeth and nails because they can betray your age, even when you have more youthful-looking skin."

Close's pale skin indicates that she doesn't spend a lot of time in the sun, and that's a good thing. "Pigmentation can become more apparent now, and sunscreen remains a must," advises Somerville. "Keep an eye on any moles that might be changing in shape, size or color; these will need to be checked by a dermatologist because nonmelanoma cancers are most common in this age group."