I'm not smart - I'm 41! You're 17! - Julia Roberts to niece Emma Roberts

While many of our favorite celebs are blessed with great genes, looking fabulous while aging requires paying attention to diet, exercise, and sticking to a beauty regimen that works for you.

Click through the gallery to see which celebs have maintained a youthful appearance, and exactly how they did it.

Which celebrities haven't been so careful about maintaining that youthful glow? Find out here!

More From Shape:
Beauty Secrets from Hollywood's Iconic Beauties
6 New Ways to Make Your Mani Last Longer
The Top 10 Ways to Boost Your Body Confidence
8 Bizarre Ways Celebrities Stay Looking Young