Fab or flop: Lena Dunham's sheer shirt, Hailey Baldwin's velvet dress and more

Summer is here, which means celebs are getting creative with sexy, skin-baring ensembles. While some looks are totally hits -- others are complete misses.

Lena Dunham turned heads this week in a bizarre, frumpy look that consisted of a sheer shirt and low-waisted, loose-fitting pants in a matching print. Mismatched red flats and a green plaid bag completed her confused ensemble. Sheer tops can work great, though, when paired with chic, demure pieces. Sarah Hyland totally nailed the sheer trend this week in high-waisted black culottes, a sheer lace top with a schoolgirl-esque white collar. White pumps and red lips completed her look. (Similar top here, culottes here.)

Day-to-night looks are perfect for summer. While sheer looks are great both day and night, Hailey Baldwin put a spotlight on another way to accomplish the task. The model donned a velvet evening dress while out and about in NYC this week. Paired with a messy bun, casual booties and sunnies, the more formal frock translated perfectly under the sun. (Similar dresses here and here.)

Click through the slideshow to see the best and worst dressed celebs of the week!

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