The blue carpet for the 2013 Billboard Music Awards saw some of our favorite stars totally transform their personal style ... with varying results!

First, the good.

Taylor Swift totally blew us away in this blue mini. The singer is known for always wearing gold princess gowns on the red carpet -- so both the color and the cut of this dress were huge changes for her. The look also let her show off her impressive legs. Loving this look.

But for the other three above, did the risks pay off as well?

Sure, it was nice to see Nicki Minaj wear a dress for once instead of another crazy outfit paired with ridiculous hair ... but this one made it look like her boobs were struggling to breathe.

The same goes for Ke$ha. While her makeunder is appreciated and we love seeing her without glitter all over the place, this dress was a major miss. The slit is way too revealing and the front of it is totally unflattering -- see it in the gallery above.

And then there's Jennifer Morrison. The "Once Upon a Time" star usually goes pretty conservative with her look, but tonight she was showing some major skin. Instead of the pant suits we've seen her in before, she put her butt on display Sunday night in a sheer dress.

What do you think of these stars' transformations? Sound off below -- and then check out pics of Selena Gomez, Jennifer Lopez and many more in the gallery above.

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