Is it possible that you heard the song and the lyrics/beat made you think of Britney, and you just kind of started imagining what it would sound like if it was a Britney song?

When I'm high on weed (sorry if that's offensive, not advocating drug abuse) I start to hear faint pop songs in the distance. They are illusions created by my mind, and the songs I hear have never been recorded or even existed. Yet, I hear them. The beats, the voices, and sometimes when I focus I can even make out some lyrics. They all sound very Britney-ish and would probably have been huge hits back in 1999-2001 if they had existed.

For example, imagine a Tivoli, Britney sitting in a glittery dress on a carousel horse, singing:

it's goes up down up down back and forth merry go round whatcha looking for, in the sun? take my hand let's have some fun candy land sugary sweet touch me there you're in for a treat

... It's easy to make up things, isn't it? Just by reading my made up lyrics and picturing the scene I described above, you can practically hear a tune and Britney's voice.