If there was a day that everyone should be born, it's on this day, Dec.18, 2017.

Some of the most famous Hollywood stars are celebrating their birthday on this day. These include celebrities such as Christina Aguilera, DMX, Brad Pitt, Sia and Steven Spielberg.

Fans will probably never forget her hits such as, "Genie in a Bottle" and "Dirrty." The Voice star turns 38. She appeared in six seasons of the NBC series.

DMX, professionally known as Earl Simmons is a rapper and record producer. And let's not forget he's also a rapper too. DMX has starred in films such as Belly, Romeo Must Die and Last Hour. DMX turns 47.

Spielberg has directed and produced some of the most popular films in history. The Color Purple, Jaws, E.T. the Extra-Terrestrial, and Jurassic Park are just a few of the films under the producer’s pallet. The pioneer turns 71.

Last, but not least, is War Machine’s very own Brad Pitt. The actor, formerly known as William Bradley Pitt, has starred in films such as Mr. & Mrs. Smith, Fight Club, World War Z, and Ocean's Eleven. The actor turns 54.

Twitter Reacts 

Fans have sent their Happy Birthday greetings to all of these celebrities. See their well-wishes below.

Tags: Celebrities Christina Aguilera Brad Pitt Steven Spielberg DMX sia Celebrity Birthdays