Justin Bieber's new album, 'Journals,' contains five unreleased tracks in addition to the 10 collected '#MusicMondays' songs he's been releasing as of late. The new tunes feature a high-caliber guest list, including the mid-tempo 'Backpack,' which features a verse from Lil Wayne.

'Backpack' features a slight switch-up from Bieber's other romantic R&B tracks in the '#MusicMondays' series. This time, the singer finds a love interest that's landed from outer space. He isn't just romancing the extraterrestrial, however. Bieber offers a bit of exposition that reveals, "They’re gonna try to take away the secrets of your planet's life / I know you must be upset, you lost your family in a wreck."

Lil Wayne is less sympathetic. While Bieber's love interest is struggling, the rapper seems to be interested in giving himself props. "When I die they gonna name this planet after me / Wayne’s world," he raps before the guitar solo kicks in.

The four other songs on 'Journals' feature Future, Big Sean and Diplo. The compilation effort is available now on iTunes.

Listen to Justin Bieber's 'Backpack' Feat. Lil Wayne