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Kourtney Kardashian and Ashlee Simpson headed to Hollywood to kick off Caesars Entertainment’s “Escape to Total Rewards,” a series of simultaneous concert events in four cities. “Im Escaping w/ @Total Rewards Lil Wayne & @CeeLoGreen tonite @ Hollywood & Highland!“ Kardashian tweeted. Click through the gallery to see Jennifer Lopez, Salma Hayek and more stars at last night’s hottest events.

Academy Awards weekend is one of the biggest party weekends of the year! Heidi Klum (in Atelier Versace), Kim Kardashian (in Azzedine Alaia) and mom-to-be Kourtney Kardashian (in Raoul) caught up at Elton John’s viewing party in West Hollywood. “The Oscar statue reminds me of Heidi Klum,” Kim told InStyle.com. “She’s golden and she’s statuesque!” So true! See more not-to-be-missed party photos from Oscars weekend in the gallery.

MORE: 
• List of Oscars 2012 Winners
• Oscars Red Carpet Fashion
• The Best Dressed Stars at the Oscars

— Betony Toht, reporting by Andrea Simpson

Have you checked out the InStyle Hairstyle Try-On App for the iPad yet? Beachy waves are one of the most tried-on styles and it’s easy to see why—the loose texture and carefree feel works on everyone. Download the app now (if you haven’t already!) to see yourself in Reese Witherspoon‘s tousled strands, Ali Larter‘s beachy bob, Kourtney Kardashian‘s lush layers, and Cheryl Cole‘s sandy waves. Plus, we just added lots of new styles, which means more celebrity ‘dos are right at your fingertips. 

See more hair beauty tips in our gallery!

MORE:
• The Newest Hairstyles of 2012
• Do You Ever Wear a Side Braid?
• Try on Jennifer Aniston’s Cover Hairstyle

Happy New Year! Where were you when the clock struck midnight? Celebrities spread out across the country for the biggest party night of the year, including Kourtney and Kim Kardashian in Las Vegas, Lady Gaga and Nicki Minaj in New York, and Vanessa Hudgens and Rihanna in Miami. And that’s not all! See all of the hottest photos kicking off 2012 in the gallery now.