Billie Eilish Weighs in on Best Billie Eilish Halloween Costumes

Billie Eilish says it's news to her that people plan to impersonate her for Halloween, but now that she knows ... here's a tip on the best costume from the woman herself.

We ran into the pop sensation Monday at LAX and asked her what look SHE would recommend to all the wannabe BEs out there. She acknowledged there are many, MANY options for her fans to replicate.

Aside from her hit music ... Billie's become a bit of a fashion icon over the past year. She's debuted a TON of unique outfits in each of her music videos. Even in this clip, she's got her own steez going strong.

One thing is clear ... Billie's having just as tough a time as her fans probably are in choosing a favorite outfit of hers. Her bottom line seems to be ... power to the people!

She did let us in on her personal Halloween plans, and she knows for sure what she will NOT be dressing up as come Oct. 31.

For those itching to make a splash with their own Billie Eilish costumes this year, you might not need to look further than her video for "all the good girls go to hell." Remember, she got (fake) tarred and feathered for that shoot ... and it's a perfectly hellish look for the occasion.

Just sayin' ...