Snapchat star Kylie Jenner channeled her inner Xtina last Halloween and dressed up as Christina Aguilera from her "Dirrty" music video. Talk about a blast from the past! More celebrities followed suit and went as other notable stars, like Justin Bieber and Kim Kardashian, and we're kind of obsessed!

The rise of celebrities dressing up as other stars has been growing over the years, thanks to social media. A lot of times when a celeb dresses up as another famous person, it's a way to broadcast their respect and admiration for the person. For example, when Kylie dressed up as Xtina for Halloween, Christina herself gave her seal of approval. "YAASSSSS"…..Killin it @kyliejenner yes to dirrty 2016!! Get it girrrl!!! ??☠️????" she captioned on Instagram.

But celebrities aren't always just fishing for an acknowledgment from their peers. Sometimes they're just crazy fans themselves doing things that we do, like dressing up as their favorite actor or singer. And let's not forget, some celebs are so iconic that they forgo being "people" and become pop culture icons. We're talking about stars like Madonna, Britney Spears, and Beyoncé. Those stars are so huge, that they're up there with Harley Quinn and "sexy" nurse costumes. We suppose you know you're famous when people start dressing up as you for Halloween! We suppose that's the ultimate compliment. It's also a good way to pull off a relevant, pop culture costume that everyone will know. The superhero and "sexy" costumes probably get tiring and are not as unique or creative as dressing up as a fellow celeb. Here's hoping the stars keep the trend alive for this year and many holidays going forward!

Check out the gallery below to see all the times celebrities dressed up as other stars for Halloween.