Celebrity Parties!

Malin Akerman (in Cushnie et Ochs) and Brooklyn Decker (in Dior) became fast friends at the after party for the Los Angeles premiere of Decker’s new movie, Battleship. “Great job in the movie,” Akerman Tweeted at the model-turned-actress. “You are one rad chica!” The sci-fi thriller—co-starring Rihanna, Taylor Kitsch and Alexander Skarsgård—hits theaters May 18th. See more stars at last night’s hottest parties in the gallery.

Mariska Hargitay welcomed friends Hilary Swank and Debra Messing to celebrate with her at the fifth annual Joyful Revolution Gala New York City, in honor of the organization she founded, the Joyful Heart Foundation. The non-profit focuses on supporting survivors of sexual assault, domestic violence, and child abuse, a cause that Hargitay became well-acquainted with after working on Law & Order: SVU. Click through to see more stars who stepped out for last night’s hottest parties.

InStyle‘s May cover girl Cameron Diaz and Chris Rock walked the red carpet at a New York screening of their new comedy, What to Expect When You’re Expecting. The film about five couples whose lives are turned upside-down by parenthood, out May 18th, explores a theme that Diaz is familiar with: getting comfortable with life’s surprises. “I’ve never said I don’t want children—I just haven’t had children yet, ” she told us in our May issue. “I don’t know what’s going to happen in my life!” See more stars at last night’s hottest parties in the gallery.

Eva Green (in Tom Ford) and Michelle Pfeiffer (in Lanvin) vamped it up for the Hollywood premiere of their new gothic movie, Dark Shadows, out this Friday. Green plays a a vengeful witch in the Tim Burton-directed film, while Pfeiffer plays a reclusive matriarch. See more stars at last night’s hottest events in the gallery.

Busy Philipps and Julie Bowen (in Prada) got in the tropical spirit to co-host a Huggies Hawaiian and Baby2Baby luau in Beverly Hills, which supported the organization’s mission to provide Los Angeles families in need with essential baby gear. “I’ve been involved with Baby2Baby since I became a new mom myself,” Philipps told InStyle.com. “You realize it takes a village and that’s why getting involved in a charity like this is so important.” Huggies pledged to donate 22 million diapers this year. See more stars at this weekend’s hottest parties in the gallery.

— Leah Abrahams, with reporting by Carita Rizzo

Emma Roberts (in RED Valentino) stayed closed to Hick star Chloe Moretz (in Dolce & Gabbana) after a screening of the new film at the Crosby Street Hotel in New York City. “Can’t wait to see your pretty face,” Roberts Tweeted to her pal before the event. In the movie, Moretz plays a Nebraskan teen who ventures to Las Vegas. Hick debuts in theaters May 11th. Click through the gallery to see more stars at last night’s hottest events.

Emma Roberts and January Jones stocked up on summer essentials at the launch party for the Shops at Target in New York City, the retailer’s new initiative featuring five different limited-edition collections by shop owners of specialty stores around the country. “I just got a pair of the Webster for Target wedges that are going to be so cute for summer,” said Roberts, who went pre-shopping for the white sweater she wore to the bash from the Webster collection, inspired by the famous Miami boutique. The Shops at Target debuts in stores and on target.com this Sunday, May 6th. See more stars at last night’s hottest events in the gallery.