Two inevitable activities occurred this week: Justin Bieber is a featured guest rapper, and Justin Bieber made an appearance on "The Daily Show with Jon Stewart."

The former can be heard on the new track from Sean Kingston, "Don't Stop," on latter's new mixtape "King of Kingz." Bieber, whose rapping abilities were captured under the joke moniker Shawty Mane starting last year, provides some singing on the chorus and some earnest rhymes that seem to make some veiled reference to fallen U.S. soldiers ("Rest in peace to all the men that died who were protecting me"). And then he name-checks John Lennon. "Trendsetta!" we hear The Bieb poke into the mix early on. Trendsetta' indeed.

"King of Kingz" dropped yesterday; the whole thing -- which also features cameos from Akon, Soulja Boy, Flo Rida and B.o.B. -- can be heard below.

Then, last night on "The Daily Show," Bieber sat in Stewart's actual desk chair (OMG), to open the night's news dressed as Stewart. The show's host came flailing in with a purple hoodie on, suggesting some witchcraft had occurred and that the two entertainers had switched bodies. All ends as well as it can, complete with a Bieber-hair joke and a lower-back tattoo promoting Bieber's "Never Say Never" film, out Feb. 11.

Check out the clip below.

P.S., welcome back to Hulu, Jon.