Of course, the spooky getup wouldn't be complete without Styles mimicking Miley's look to the letter, which wasn't too difficult considering he was there when it happened.
Not only did he stick out his tongue and flash two fingers for the camera, but Styles also wore a massive foam finger similar to the one Cyrus used during her controversial VMAs appearance, where she popularized twerking for the masses while bumping and grinding against Robin Thicke while the latter sang his hit "Blurred Lines."
Styles isn't the only celeb to go as Miley for Halloween, which proved to be one of the most popular costumes this year. E!'s own Joan Rivers got in on the fun, as did The View's Jenny McCarthy, singer Paris Hilton and morning talk show host Kelly Ripa.