Singer tweets she's 'happy to be back again' after entering a rehab facility in January.
Pusha T, Schoolboy Q and Wiz Khalifa also show up in the clip.
We can now watch Justin Bieber submitting to a drug test, but do we really need to?
Not only does the 17-year-old serve as the official DJ on the "Neon Lights" tour, but as Demi's hair inspiration as well.
Perry laughs off feud with a cheeky (and a tad violent) response.