Actress Demi Moore poses as she arrives at The Creative Coalition dinner during the Sundance Film Festival in Park City, Utah
Actress Demi Moore poses as she arrives at The Creative Coalition dinner during the Sundance Film Festival in Park City, Utah Reuters/Mario Anzuoni

Some of Hollywood's biggest stars managed to stay on top and successfully overcame the aging process by combining regular exercise, a healthy lifestyle and a low-fat diet.

Here are the top five fittest stars over 50 years of age and their secrets.

1. Brad Pitt

One of the hottest male actors in Hollywood for decades is turning 51 years old on December 18, 2014. Pitt stays fit by doing sword work and hitting the gym at least three times a week. The star of "Interview with the Vampire" looks ageless by staying off unhealthy and fatty food and living a wholesome lifestyle with Angelina Jolie and their children.

2. Demi Moore

The star of "Ghost" can conveniently date men half her age because even at 51 years old, she is still flawless and can wear a bikini to show off her rock-hard abs any day of the week. Demi Moore loves to hit the gym regularly and stays on a lean and low-fat diet regimen to maintain her toned figure. After separating from the much younger Ashton Kutcher, Demi has been spotted going around with Sean Friday, who is just two years older than Demi's daughter.

3. Johnny Depp

For several years, the star of "Pirates of the Caribbean" has topped the hottest celebrity list for many good reasons. Johnny likes to use his bodyweight when working out, doing squats, pushups and pull-ups to tone his body. The Examiner reveals that his daily fitness regimen involves strenuous workout routines, including two-mile runs daily and a lot of muscle exercises. Depp has also decided to stay away from alcohol and said to be vegan.

4. George Clooney

Clooney was born on May 6, 1961 but looks way better than many half his age. According to FitSavvy.com, Clooney does hundreds of pushups and pull-ups every week. He also likes to go on long runs to de-stress and chisel his body.

5. Julianne Moore

Moore is turning 53 years old in 2014 but maintains a toned and trim figure by doing Ashtanga yoga two to three times each week. She also shared that working with a trainer helps intensity her workouts. She choose the right kinds of food like vegetables and stays away from sugar as much as possible. She also does juice cleansing every few months to detoxify.