Cause you know I'm all about that... baaaad guy.

Pop princess Meghan Trainor recently stopped by BBC Radio 1 to promote her third studio album Treat Myself (due out Jan. 31). Toward the end of the interview, host Scott Mills engaged Trainor in a round of "Your Lyrics Different Song," asking her to perform the words from one of her hits over the tune of another.

Singing to the music of Billie Eilish's "Bad Guy," Trainor revamped her 2014 hit "All About That Bass" — turning the throwback summer anthem into a chilling remix.

She only sang the first chorus and verse, but was instantly sold on the strength of her new hit.

"Wow, yeah. I got lost, I just got lost. This is a fuckin' bop!" she joked. "I left all of you guys for a moment, and was like, 'Why is this my favorite song?'"

Trainor later shared a clip of the interview on Instagram, tagging Eilish. Here's looking at the 2020 collab the internet now demands. We're thinking "Dear Future Xanny" ... or something like that?