If you watched the Oscars on Sunday, you surely noticed the seemingly flawless smiles on the celebrities’ faces—particularly the ones who won an award. Their smiles didn’t just happen naturally though. Their pearly whites and amazingly straight teeth came from a lot of dental work and upkeep.

Why would they go to such lengths to perfect their teeth? Celebrities are under constant scrutiny, not only from their fans but from production companies and producers as well. Some actors would not have landed the parts that brought them to fame if they had not corrected their teeth. Robert Pattinson, for instance, was told he had to fix his teeth before he could play Edward Cullen in the Twilight series–a role that brought him into the spotlight.

While we won’t be able to mention every celebrity who has had cosmetic dental work done, because that would clearly take too much time, here are 5 celebrities we believe have had the best celebrity smile makeovers, one of which may shock you!

Christian Bale

One of the 2014 Oscar nominees for his performance in American Hustle, Christian Bale didn’t always have a perfectly straight set of teeth. You may remember him well from his performance in The Newsies, but had you ever noticed the drastic change in his teeth? His celebrity smile makeover caused his teeth to become much straighter, boxier and whiter. He has admitted that he did have extensive dental work done before he filmed American Psycho. And while his smile is one of the most notable smiles in Hollywood, the actor has said how much he misses his smile from before.

Hilary Duff

For some celebrities, you don’t even really think they need work done until you see the end result. Hilary Duff is one of those celebrities. Although slightly yellow, her natural teeth were still straight and perfectly aligned. No one would have thought to tell Hilary Duff to get work done, other than maybe using some teeth whitening strips. However, some celebrities do have to get work done if they experience any type of dental emergency–just like anyone else would.

At the height of her musical career, Hilary Duff actually chipped one of her front teeth on her microphone when she was performing. Although I’m sure her dentist could have done something minor to fix her tooth, Hilary Duff decided, for whatever reason, to get veneers. Her first set of veneers-were much too big. They looked completely unnatural. Fortunately, she had them redone creating a much more natural look and a flawless smile, as you now see in the picture to the left.

If you’re envious of her smile, just remind yourself of the cost. Veneers are a permanent change and cost thousands of dollars. Veneers can run anywhere from $1,000 to $5,000 per tooth. So while most celebrities can afford this type of procedure, it’s definitely not for everyone.

George Clooney

Another face we’ve seen at the Oscars many times is George Clooney. His teeth have also sought some major improvements as a result of a very bad habit dentists advise you to stop–grinding your teeth.

For the full implications of what grinding your teeth can do to the appearance of your smile, take a look at George Clooney’s natural teeth. You’ll notice they are very small and uneven when you compare the back to the front. In contrast, when you see him smiling today, in the picture to the left, you can see his teeth appear larger, whiter and even. It can be assumed from his pictures that George Clooney most likely had porcelain veneers to lengthen his teeth or gum surgery that would have used lasers to move up the gumline and expose more of his teeth.

It’s not clear what route he took to correct his teeth, but whatever he did has caused a major improvement.

What lesson can we learn from George Clooney? Don’t

Catherine Zeta Jones

Catherine Zeta Jones had a drastic smile transformation. Comparing her old and new smile, it can be safely assumed veneers came into the picture at some point. But many speculate that there was a period where she did have some type of orthodontics to correct the gap and alignment of her teeth. Had she not been in the spotlight, orthodontics and teeth whitening probably would have been enough.

Tom Cruise

When you compare Tom Cruise’s smile now with that of him before, you’ll be shocked at the comparison. This iconic actor just wouldn’t be the same without the smile he now carries. His dental work was not only cosmetic. It was vitally important Tom get some work done on his teeth for the sake of his oral health. His teeth were previously misaligned and his front tooth jutted out. This would have caused him so many problems later down the line had he not fixed it.

He has had invisible braces and a couple of veneers to correct the problem, but it wouldn’t be too surprising if he had to have more than that done. And although his smile has majorly improved, this is one actor whose smile is still not perfect. If you’ll notice in the picture on the right, his two front teeth are not where they should be. They are still misaligned. It’s not clear why his dentists have left his teeth this way, but his smile has still improved a great deal since he was a young actor.

What celebrities do you think have had the best celebrity smile makeovers?