Inside the Party: Gwyneth Paltrow, Sarah Jessica Parker, Kate Hudson, and More Toast to Tiffany & Co. Inside a 31-Foot Tall Tiffany Blue Box

“I love the color, it’s one of my favorites,” Gwyneth Paltrow said of the celebrated hue of the evening—Tiffany Blue—at the jewelry company’s Blue Book Ball, which took place inside a 31-foot-high Tiffany Blue Box covering The Rink at Rockefeller Center. “It’s so optimistic and it’s perfect. I think it’s so beautiful.” Inside, these two were among 400 guests who were treated to a ’20s-style supper club, complete with big-band jazz performances and a serenade by Smash star Megan Hilty, who fittingly performed the anthem of the evening, “Diamonds Are a Girl’s Best Friend.”

Carey Mulligan shed her Prada costumes for the evening—“I probably am yeah stay away from the era a little bit,” she told reporters at Tiffany amp Co.'s Blue Book Ball, which took place inside a 31-foot-high Tiffany Blue Box covering The Rink at Rockefeller Center—and opted for a sleek Victoria Beckham look instead. Though, she continued to accessorize with $855,000 worth of Tiffany amp Co. jewelry—the company behind the jewels she wears in the forthcoming period film, The Great Gatsby. Kate Hudson (in Reem Acra) and Michelle Williams also accessorized with Tiffany, Hudson in $256,195 worth of jewels and Williams in $900,000 worth. Fancy!

Co-stars Heather Graham (in Stella McCartney) and Zac Efron (in Balenciaga) posed together at a special screening of their film At Any Price, held by The Cinema Society and Bally at the Landmark Sunshine Cinemas in Manhattan. "The cast that came together was pretty extraordinary," Efron told InStyle.com of the movie, which opens April 26. "I’d pinch myself every time I looked up. And having Heather in the movie was pretty phenomenal. That was a surreal moment for me, just being with her."

Amy Smart and Emmanuelle Chriqui pulled out their green thumbs in Los Angeles, where they attended the Environmental Media Association's celebration of Earth Day, which is April 22.

Julianne Moore (in Dolce & Gabbana) and Chloe Grace Moretz (in Marni) attended a photo call for their film, the re-make of the classic horror movie Carrie, at the Fifth Annual Summer of Sony in sunny Cancun.

Usher and Oprah Winfrey were on-hand to help induct legendary musician Quincy Jones into the Rock and Roll Hall of Fame in Los Angeles.

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's May cover girl Emily Blunt (in Miu Miu) and her husband John Krasinski attended the after-party for the premiere of Blunt's new film Arthur Newman in Hollywood. "Meeting John really changed my life,” Blunt told InStyle. “When I feel the support that I have from him, I feel invincible. There’s someone behind you on your good days, and someone in front of you on your bad days.”

Elizabeth Banks and Liam Hemsworth attended a CinemaCon Press Conference hosted by production company Lionsgate in celebration of its 2013 release schedule, held at Caesars Palace in Las Vegas.

It was ladies night at CinemaCon in Las Vegas, where funny gal co-stars Sandra Bullock (in Roland Mouret) and Melissa McCarthy came in close for an embrace on the red carpet.

Uma Thurman joined Calvin Klein’s Womenswear Creative Director Francisco Costa at the label’s cocktail party thrown in honor of the Human Rights Campaign’s recent strides for marriage equality with their Americans for Marriage Equality program in New York City. "I’m a longtime fan of Calvin Klein," actress Uma Thurman said. "Tonight, they lured me upon the issue of marriage equality. To me, it’s an absolute no brainer. Hopefully, it will be alleviated soon and everyone will be allowed to marry and divorce equally!"

The How I Met Your Mother star and his partner David Burtka were also on hand to lend their support to an issue that’s very close to their heart. “We’re big supporters of the Human Rights Council and we think it’s a good time to show extended visibility given the recent tipping point on pro-marriage equality,” Harris told us. "It’s nice to be a couple during this time and not 30 years ago."

Sir Elton John brought two of his favorite ladies, Kate Hudson (in Ann Taylor) and Elizabeth Hurley (in Blumarine), in close at the Breast Cancer Foundation's Hot Pink Party at New York's Waldorf=Astoria Hotel.

Amy Smart and Alanis Morissette attended Kiehl's launch party for their environmental partnerships benefiting Recycle Across America. Morissette designed packaging for the brand.

Miranda Kerr and John Travolta attended the Qantas Gala Dinner held in Sydney, Australia. The airline hosted the dinner inside a giant hangar located at the Sydney Domestic Airport.

Sally Field and Joseph Gordon-Levitt honored film producer Kathleen Kennedy at a special dinner hosted by the Will Rogers Motion Picture Pioneers Foundation in Las Vegas. Kennedy, who produced the Oscar-winning film Lincoln, was given the 2013 Pioneer of the Year Award during the evening's festivities.

In Century City, California, Alexis Bledel (in Pamella Roland) and Zachary Levi (in Vivienne Westwood Man) premiered Remembering Sunday, their ABC television movie about a woman who falls in love with a man with short-term memory loss. The movie airs on ABC and the Hallmark Movie Channel Sunday, April 21 at 9/8c.

Jennifer Hudson (in Ungaro) and Brittany Snow (in Naeem Khan) attended the world premiere of Lifetime's special five-part film series Call Me Crazy: A Five Film last night in Los Angeles. The series of five shorts, each directed by and starring different personalities, focus on different scenarios of what happens to the loved ones of people coping with mental illness. "I wanted to be a part of it because I felt like making awareness about mental illness is important," Hudson told reporters at the screening. "It’s such a great project to be a part of and I’m so proud of it."

Sienna Miller turned out in a floral embellished LBD by Topshop for the Tribeca Ball, the annual bash held to open the Tribeca Film Festival in New York.

Supermodel Doutzen Kroes gave a tight squeeze to performer Kianna Cotton after she took the stage at the Garden of Dreams Foundation's 2013 talent show Dare to Dream at Radio City Music Hall in New York. The non-profit works the Knicks, Rangers, Liberty, and Madison Square Garden-related partners to makes dreams come true for children facing difficulties, like illness, homelessness, poverty, foster care, and tragedy.

Jordana Brewster (in BCBG Max Azria) and Paul Walker posed together at Nobu after a special presentation of their slate for Fast and Furious 6 in Las Vegas. The movie opens May 24.

Cute couple Chrissy Teigen and John Legend shared a table with Elizabeth Olsen (in Chloe) at City Harvest's 19th Annual Evening of Practical Magic, held in honor of Benchmarc Events chef and owner Marc Murphy, at Cipriani 42nd Street in Manhattan. City Harvest works to end hunger for all New York City residents.

Heather Graham and Dennis Quaid attended the Los Angeles premiere of their film At Any Price, which opens in theaters April 26.

Jake Gyllenhaal attended Edible School Yard New York City's spring benefit, A Garden Grows in Harlem, where he and other guests nibbled on dishes prepared by more than 20 of New York's finest chefs. The benefit was held in part to celebrate the non-profit's recent expansion into East Harlem.

It was a reunion of seasoned actors at the Mardi Gras-themed National Dance Institute Annual Gala in New York, which raised money for the non-profit’s mission of providing arts education programs to public school children in under-resourced neighborhoods of New York City. Bernadette Peters presented Mandy Patinkin with the organization’s top honor in recognition of his commitment to arts and culture in NYC. “I’m the grateful one,” he told InStyle.com told InStyle.com, noting that his two children were in NDI. “It deeply formed their lives in form of community, and put into their bodies a sense of confidence that they took with them everywhere. I’m honor them for the gift they gave to our family.”

Chris Pine (in Z Zegna) was all smiles as he arrived to a special Paramount Pictures presentation that promoted the upcoming Star Trek Into Darkness sequel, which hits theaters May 17.

Mark Wahlberg and 50 Cent attended a screening of Wahlberg's film Pain and Gain, hosted by Men's Fitness and The Cinema Society, in New York. The movie, which opens April 26, tells the story of a trio of bodybuilders who get caught up in a botched kidnapping scheme.

Bruce Springsteen, Sting, and Robert De Niro were a powerful support network for actress Rita Wilson, who gave her first-ever singing performance at New York's 54 Below.

Will Smith and Amy Poehler attended Keep Memory Alive's 17th Annual Power of Love Gala in Las Vegas, which benefited the Cleveland Clinic Lou Ruvo Center for Brain Health. The clinic, which has Vegas-based treatment centers, works specifically to combat brain diseases and help those people afflicted with them.

Emmy Rossum honored singer Diane Warren and celebrity photographer Christopher Ameruoso for their efforts on behalf of animal welfare at The Saving Tails event hosted by The Onyx & Breezy Foundation in Los Angeles.

A pregnant Fergie (in Fausto Puglisi) and Kylie Minogue posed on the red carpet at the New Now Next Awards, an evening dedicated to emerging talent in film, TV, music, and new media, held at The Fonda Theatre in Los Angeles. The Black Eyed Peas frontwoman was honored with the Always Next, Forever Now Award.

Selena Gomez (in Peter Pilotto) shared a moment with RuPaul backstage at the New Now Next Awards in Los Angeles where the pop star was honored with the Triple Play Award.