Paris Hilton had the best time of her life as she turned 40.

In just one day, the hotel heiress celebrated two milestones in her life--first is her birthday and the second is her engagement with boyfriend, Carter Reum.

The hotel heiress and his now fiance, who is an entrepreneur and M13 Ventures founder are now ready to move onto the next chapter of their life after only dating for a year.

Paris Hilton's Beauty Secrets

Who would have thought that the "Simple Life" star is now 40? This only shows that the reality star turned model and now dj and entrepreneur prioritizes her wellbeing and maintains a strict beauty regime.

In her previous interview with W magazine, the socialite, who at that time was launching her Glam App, details on how she keeps her skin youthful.

Despite her busy schedule, the self confessed boss babe shares one of her biggest skincare rules--and that is using sunscreens.

The "House of Wax" star explained that at a young age, she and her sister Nicky, was taught by her mom the importance of skincare.

"My mom's number one rule that she enforced was to stay out of the sun and to use sun protection. As a teenager, when my friends were baking in the sun, I was that girl with a giant hat sitting under the shade. And I am so happy that I listened to her," she mentioned.

How to Achieve Paris Hilton's Age Defying Look

Long before the 10-step korean skincare, the "Hottie and the Nottie" actress has been using face products such as eye creams, neck creams, and serums.

Using these anti aging products regularly slows down visible signs of aging and helps combat free radicals that are causing harm to the skin.

During her Harper's Bazaar "Go To Bed With Me" video she revealed her nighttime routine that mostly consists of her beauty brand, Paris Hilton Skincare.

Paris Hilton PRO D.N.A. Dual Action Cleansing Gel

First, she used her PRO D.N.A. Dual Action Cleansing Gel from her brand that is formulated with natural ingredients.

She described it as her favorite cleanser since it can effectively cleanse and gently exfoliate the skin.

Paris Hilton Skincare Lift and Firm Eye Cream

As mentioned above, the hotel heiress is a firm believer of using eye creams.

The eye-brightening cream contains a silky formula that can easily penetrate into the skin. This can help restore vibrancy and brightness around the eye area.

Dr. Barbara Sturm's Anti-Pollution Drops

She also swears by using the Anti-Pollution Drops from Dr. Barbara Sturm that said to protects the skin's barrier from pollutants.

Paris Hilton Pro DNA Advanced Recovery Serum

Last but definitely not the least in her 10-step skincare is the Pro DNA Advanced Recovery Serum.

This advanced recovery serum works at the deepest level of the skin to help the cell regenerate making it supple and youthful.

Paris Hilton and Carter Reum's Engagement

The soon to be bride lit up the luxurious private island with her stunning Margarita Dress in Snow White from the New York-based high contemporary brand, Retrofête.

According to the website, the hand-stitched embellished maxi dress retails for $1,145.

Interestingly, the best highlight of the day was none other than her breathtaking mega-carat ring made by the famous jeweler, Jean Dousset, who was said to be the great-great-grandson of the legendary French jeweler Louis Cartier.

Over her website, Paris Hilton's engagement ring was handcrafted for the blonde beauty and was even named after her.

"A group of finest diamond cutters, polishers, jewelers, and setters, were assembled for this special project," the statement reads.

The 20-carat emerald-cut jewelry also featured trapezoid diamonds on each side, that costs a staggering $2 million, as cited by WP Diamonds CEO Andrew Brown in a news obtained by E! News.

READ MORE: Huda Beauty's New Bomb Brows Comes with Microbladed-Like Effect