Watch Justin Bieber And Iggy Azalea Lip Sync Their Hearts Out

And the "Empire" cast, and Alison Brie, and "Broad City"...

You've already seen Dwayne Johnson shake off Taylor Swift and Anne Hathaway wreck Miley Cyrus, but now it's Justin Bieber and Iggy Azalea's turn to do their worst on Spike TV's "Lip Sync Battle."

A new promo for the series -- which returns on July 9 -- shows Bieber and Azalea lip synching for probably the first time ever (zing!), but they're not alone. Alison Brie also does what looks to be a pretty stellar rendition of "Bang Bang," Terrence Howard takes on his "Empire" wife Taraji B. Henson with a disco-tastic take on "Brick House," and Will Arnett goes back to his roots with "Everything is Awesome."

Oh, and did I mention that the girls from "Broad F--king City" are joining in on the fun? No, I did not. But I will now.