Billie Eilish might be 17, but she already gives off that "serious artist" vibe . . . which is why some folks are finding 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 younger Billie in her bedroom, surrounded by Justin Bieber posters. She put the picture on Instagram with the caption, "OMGFFFFGGG ANYTHING IS POSSIBLE MAN."