Happy Birthday to Katie Holmes, Brad Pitt, Christina Aguilera, Tara Conner and DMX!

Who knew December 18 would be such a huge day for celebrity birthdays?

Two of our five featured celebs are acclaimed actors (and form parts of huge Hollywood power couples). One has been nominated for a dozen Grammys and sold 42 million albums. Another was nearly stripped of her Miss USA crown after cocaine and alcohol abuse (plus girl-on-girl action). The last raps and has been arrested like 79 times.

Give it up for Brad Pitt, Katie Holmes, Christina Aguilera Tara Conner and DMX!

Here's a little photo tribute to the birthday boys and girls. Click to enlarge ...