Britney Spears is really sexing up her look ... and we love it!

The "X Factor" star made some vast improvements to her wardrobe this week -- ditching the dresses for some super-tight pants and sexy tops.

The singer wore very similar-fitting outfits twice this week, sporting black leather pants and revealing red blazer on Wednesday night's show ... and following it up with a low-cut sparkly top and black jeans last night.

When paired with her new 'do, this is the most youthful we've seen her look in a while. It's really working for her!

Check out the gallery above to see how her style has evolved since she joined the show. What's your favorite outfit she's rocked so far?