L.A.'s Staples Center was the place to be on Monday, July 1, when Beyonce took the stage for the third show on the U.S. leg of her Pepsi-sponsored Mrs. Carter World Tour. Celebs packed the house to watch Jay-Z's wife work the sold-out crowd of tens of thousands of fans, giving the already super-powered event an extra dash of Hollywood glitz and glamour.

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As Us Weekly previously reported, recently single Robert Pattinson was in attendance at the show, wearing a backwards baseball cap, jeans, boots, and a vintage MTV varsity jacket. But he wasn't the only A-lister in the arena -- far from it, in fact.

Glee's Kevin McHale was also in the crowd, along with pregnant costar Heather Morris, who was a backup dancer for Beyonce before she landed the role of Brittany on the FOX series. (Morris performed the iconic "Single Ladies" dance alongside Chris Colfer's character in one of the very first episodes of season one.)

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"Heather looks super pregnant -- she was wearing a long, tight dress and holding her belly," an onlooker told Us of the mom-to-be. "She looked really happy though!"

Dell's VIP area in the HYDE Lounge, meanwhile, played host to Morris' costars Lea Michele, Chris Colfer, and Naya Rivera, who brought boyfriend Big Sean. A source tells Us Weekly that Rivera and Big Sean were kissing and dancing throughout the night, to tunes including "Run the World," "Halo," and "Single Ladies."

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Elsewhere in the Dell-hosted section, Captain America star Chris Evans cozied up to girlfriend Minka Kelly, while Karina Smirnoff and Tiffani Thiessen played dress-up in the Dell photo booth. Toward the end of the night, Smirnoff's Dancing With the Stars pal Derek Hough challenged another guest to a dance-off.

Other celebs in the audience included Kourtney Kardashian, who stood front-row with sister Kendall Jenner and documented her amazing view of the stage on Instagram. Australian pop star Kylie Minogue also snapped a pic of Beyonce, which she captioned: "The Queen had her #beyhive buzzing...Flawless show. #Flawless!"

This article originally appeared on Usmagazine.com: Beyonce Concert in L.A. Draws Pregnant Heather Morris, Kourtney Kardashian, Minka Kelly and Others