Whether they went spooky or sexy, Hollywood's hottest couples got into the spirit of Halloween by dressing up in a wide variety of costumes. 

90210 star Shenae Grimes enlisted Project Runway alum Chris March to design a custom look modeled after Mattel's Frankie Stein, a character from the toy manufacturer's Monster High series. "When I get dressed up on Halloween I like to look like a monster," the 23-year-old actress told InStyle. "You've got to be a glamorous ghoul, so to speak."

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Grimes' boyfriend, musician and model Josh Beech, wore matching zombie makeup and a black blazer. The lovebirds debuted their looks at Matthew Morrison's third annual Halloween party at Lure nightclub in Hollywood Oct. 28.

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Julianne Hough and Ryan Seacrest, meanwhile, found costume inspiration from the 1967 crime caper classic Bonnie and Clyde, which starred Warren Beatty and Faye Dunaway. "No face paint, no wig, no spandex. . . winner," Seacrest, 37, tweeted hours before he and Hough, 24, hit up a bash in Beverly Hills Oct. 26. Hough also dressed her two dogs in coordinating looks. "Lexi and Harley were framed for what Bonnie and Clyde did," the Safe Haven star wrote on Instagram. "They look scared in their prison outfits."

Fashion designer Lauren Conrad, 26, looked haunting in a self-designed ghoul costume, while her University of Southern California law school student beau, William Tell, 32, looked sinister as Frankenstein. "Boo," Conrad wrote in an Instagram caption.

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Paris Hilton, 31, wore a sexy Alice in Wonderland-inspired costume in L.A. Oct. 24, while her model love, River Viiperi, 21, channeled the Mad Hatter from the beloved Lewis Carroll novel. "So excited for Halloween this year!" the hotel heiress wrote on Instagram earlier that week. "I love getting dressed up in costumes!"

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Other celebrity couples who dressed up over the weekend include Fergie and Josh Duhamel, Morrison and Renee Puente, and Christina Aguilera and Matthew Rutler.

Tell Us: Which celebrity couple wore the best Halloween costumes in 2012?

This article originally appeared on Usmagazine.com: Which Celebrity Couple Wore the Best Halloween Costumes?