Sexy Stars: Kourtney Kardashian's sheer dress, Gisele's vinyl pants and more

Sexy mamas!

Kourtney Kardashian, 37, put her hot revenge bod on display in a gauzy, sheer black lace Nina Ricci dress that exposed some skin. (Similar here and here.) Casual, flowing locks, sexy sandals and simple makeup completed her effortless look.

Mother-of-two Gisele Bundchen also turned heads this week in another hot look. The 35-year-old model wowed on the "Tonight Show" in outrageously sexy vinyl pants, which was offset by a cozy gray crewneck sweater and flirty high ponytail ... Sure beats the typical bandage dress and pumps combo! (Shop similar pants here and here.)

SEE ALSO: Kylie Jenner sizzles in her sexiest bikini snap yet

It wasn't all about the ladies this week. Nick Jonas, 23, surprised fans with a pop-up performance at a workout class in Venice Beach this week -- and looked totally dapper in black skinnies, shoes and a navy bomber jacket. Talk about sexy ... the "Jealous" singer definitely wasn't the only one who needed to rehydrate with Propel water!

See these looks and more in the slideshow above.

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