Kim Kardashian Shares Bikini Pictures With North West; Adrienne Bailon

Twins! Kim Kardashian shared pictures of herself and her daughter North West wearing color coordinated swimsuits on the beach in Mexico. Plus, Rob Kardashian's ex-girlfriend Adrienne Bailon responds to the Kardashians after she bashed their brother. Check out the rest of Us Weekly's top stories from July 31 in the round-up below!

1. Kim Kardashian Shares Bikini Pictures With North West From Mexico Vacation -- See the Snaps Here!

Too cute! Kim Kardashian shared pictures of herself and her daughter North West having fun on the beach in Mexico.

2. Adrienne Bailon Defends Rob Kardashian Comments: "We All Learn From Our First Loves"

Eek! After Adrienne Bailon bashed her ex-boyfriend Rob Kardashian -- and then got serious heat from the Kardashian sisters -- the former Disney star spoke out again defending herself and her comments.

3. PICS: Jill Duggar and Husband Derick Dillard Enjoy Lunch Date at His Workplace: See the Cute Photos

19 Kids and Counting star Jill Duggar joined her husband Derick Dillard for lunch at work. The newlywed shared an adorable snap of them eating with the caption: "Lunch with my best friend at his workplace."

4. Justin Bieber, Orlando Bloom Feud: Celebrities React, Take Sides

Ha! Celebrities have joined in on the epic fight between Orlando Bloom and Justin Bieber after the two got into it over Miranda Kerr in Ibiza. Find out which celebs are #TeamBieber and which are #TeamOrlando.

5. Hilary Duff Wrote Song About Estranged Husband Mike Comrie in New Album: "Maybe We Are" Meant to Be

Hilary Duff revealed to Billboard.com that she turned to music following her separation from Mike Comrie. The songstress added there is also a song on her upcoming album about whether she and Comrie are meant to be together or not, adding it's "very, very personal."

Rihanna Parties in Her Undies

We see London, we see France: Rihanna went out clubbing in boxers and a bra top on Wednesday. (Splash News)

Somebody should tell Rihanna that she keeps wearing clothes that are meant for inside outside.

The 26-year-old "Diamonds" singer went to a New York City nightclub on Wednesday wearing a small black bra top and roomy white boxer shorts. Yep, it was pretty much underwear that she uniquely paired with high-heeled sandals, an oversized dark denim jacket, and deep purple lipstick.

The Barbadian beauty — who is back from Detroit, where she had been rehearsing with Eminem for their upcoming Monster tour — wore the ensemble to Manhattan's VIP Room, where she attended R&B singer Jeremih's "Don't Tell Em" single release party. And, despite recent brushes with a stalker in NYC, she seemed to be in a good mood as she arrived, even snapping a selfie with an excited fan.