BILLIE EILISH might be 17, but she already gives off that “serious artist” vibe . . . which is why I found it odd that her childhood hero was JUSTIN BIEBER.

But he was…and Billie finally got to collaborate with him, when he added vocals to a remix of her hit song “Bad Guy”.

And the cover art shows a young(er) Billie in her bedroom, surrounded by Justin Bieber posters.  She put the picture on Instagram with the caption, “OMGFFFFGGG ANYTHING IS POSSIBLE MAN.”  In all caps, yes.