Celebrity Britney Spears Shows Off Bikini Body on a Family Vacation, Plus More Celebrity Instagrams from the Weekend By Rita Kokshanian Rita Kokshanian Rita Kokshanian is a Los Angeles-based writer and editor who covers celebrity, fashion, beauty, and lifestyle. She was previously an Assistant Editor for InStyle and is currently the Senior Copywriter at The Grind. InStyle's editorial guidelines Updated on March 30, 2015 @ 01:15PM Pin Share Tweet Email Photo: Instagram/@britneyspears It was an action-packed weekend for celebrities, and they proved it with their Instagram snaps. Britney Spears posted a too-cute photo of herself (clad in a bikini) splashing in the waves in Hawaii with her two sons, Jayden and Sean, while Demi Lovato also shared a sweet photo of herself enjoying the sunny weather with her puppy while wearing a two-piece. Meanwhile, Justin Bieber goofed around with Kourtney Kardashian’s son Mason, while Rihanna watched her new movie Home front-row in a theater. See these and more of our favorite Instagrams from the weekend below: Demi Lovato: Justin Bieber: Rihanna: Michelle Obama: Ariana Grande: Olivia Palermo: Mariska Hargitay: Sofia Vergara: Michelle Rodriguez: The Best Instagrams from Last Week