What a difference!

Before and After Cosmetic Surgery: 'The Hills' Star Heidi Montag's Transformation

Heidi Montag became known after starring in the 2006 MTV series The Hills. Over the years, the now 34-year-old has undergone several plastic surgeries. Here is the stark transformation of The Hills star.

After the first season of the reality series was released, Heidi Montag had her nose corrected and her breasts enlarged in 2007. At that time she wasn't even 21 years old. A few years later, Montag underwent further plastic surgeries - a total of ten in just one day. Heidi's sudden change was more than evident.

Watch the video to see Heidi's transformation!