Charli XCX -- Good Genes or Good Docs?!

Charli XCX 's looks over the years are so BRATTY!

Here is a 21-year-old version of the singer-songwriter, "fancy" in leather, at the mtvU Woodie Awards and Festival in Texas back in 2014 ( left ). This was the same year she collabed with Iggy Azalea on "Fancy" and dropped her hit song "Boom Clap."

And a decade later, Charli recently stayed true to her fierce leather roots -- making a visit to "The Howard Stern Show" ( right ) and discussed all things "Brat Remix" -- her new album which dropped earlier this week.

How do you like them apples?!

The real question here is: