Double Trouble: Hollywood's Halloween Costume Copycats

Lauren Conrad dressed as a flapper in 2008.

Kim Kardashian rocked a '20s-inspired costume in 2008.

Paris Hilton dressed as a sexy mermaid in 2013.

Kim Kardashian went under the sea in 2012.

Mariah Carey showed skin in a mermaid costume at her 2003 NYC bash.

Kourtney Kardashian and Scott Disick arrived at a Miami Halloween party dressed as Batman and Robin in 2012.

Paris Hilton and then-boyfriend River Viiperi donned Batman and Robin costumes in 2012.

Kim Kardashian slipped into Catwoman's infamous black suit for a Miami party in 2012.

Brooke Burke channeled Catwoman at an LA event in 2010.

in 2014, Nicole Richie dressed as Cruella de Vil while her cute kids, Harlow and Sparrow, were little dalmatians.

Iggy Azalea hit the red carpet as Cruella de Vil in 2013.

Aubrey O'Day went the sexy Cruella route in 2015.

Lauren Conrad went for the nautical look in 2007.

Paris Hilton dressed as a sexy sailor in 2007 as well.

Audrina Patridge went as Madonna to a LA party in 2007.

Sarah Michelle Gellar went all out for her Madonna costume in 2013.

Lauren Conrad DIYed her sweet Minnie Mouse costume in 2011.

Paris Hilton channeled the Disney character in 2014.

Miley Cyrus channeled Nicki Minaj with her costume in 2012.

Paris Hilton hit the town as MTV VMAs Miley Cyrus in 2013.

Kelly Ripa and Michael Strahan did their best impression of Miley Cyrus and Robin Thicke in 2013.

Crystal Harris and Hugh Hefner also channeled Miley Cyrus and Robin Thicke in 2013.

Fergie's Toddlers & Tiaras look came complete with a trophy and teddy bear at an NYC Halloween party in 2011.

Chrissy Teigen perfected her pageant-girl look in 2011 (at the same party as Fergie!).

Candice Accola went as a toddler in a tiara, while her Vampire Diaries costar Zach Roerig dressed as her coach in 2011.

Christina Aguilera made an arresting sight as she left a Halloween party dressed as a cop in 2010.

Paris Hilton did her best police officer impression at an LA party in 2006.

Khloé Kardashian laid down the law for a Halloween bash in 2007.

JWoww went all out as the Queen of Hearts at the Night of the Living Drag event she hosted with Snooki in NYC in 2013.

Alessandra Ambrosio went to the Casamigos Halloween Party as a sexed-up Queen of Hearts in 2013.

Snooki and JWoww opted for a costume change at their 2013 Halloween event, switching it up as Tweedledee and Tweedledum.

Aisha Tyler's 2012 costume got pretty elaborate: she was the Cheshire Cat.

Kim Kardashian mastered her Queen of Hearts look in 2010.

Amber Rose dressed up as Slash from the '90s rock band for Heidi Klum's annual Halloween bash in 2011.

Jessica Alba and Kelly Sawyer were dressed as Axl Rose and Slash at Kate Hudson's Halloween party in 2014.

Cindy Crawford and Rande Gerber were impeccably dressed as Axl Rose and Slash for an LA party in 2013.

In 2011, Adam Levine and Anne Vyalitsyna drew inspiration from the classic Guns N' Roses video for "November Rain."

Bethenny Frankel channeled Marilyn's Old Hollywood glamour at Heidi Klum's annual Halloween party in NYC.

Kate Upton took a scarier take on Marilyn's pinup-girl look for an NYC bash in 2011.

Katie Couric got all dolled up as the Gentlemen Prefer Blondes Marilyn in 2005.

Shenae Grimes dressed as Poison Ivy from Batman at the Midori Green Halloween party in LA in 2013.

Kim Kardashian attended the Midori Green Halloween costume party as Poison Ivy in 2011.

Neil Patrick Harris, David Burtka, and their twins, Harper and Gideon, were the epitome of cuteness as the Tin Man, Scarecrow, Dorothy, and the Cowardly Lion in 2012.

Jason Biggs went all out with his Dorothy Gale costume in 2005.

Martha Stewart made the perfect Glinda the Good Witch in 2013.