Justin Bieber Crashes Mariah Carey Recording Session: See French Montana's Photo

Chelsea Lauren/WireImage
Justin Bieber performs at 102.7 KIIS FM's Wango Tango at StubHub Center on May 9, 2015 in Los Angeles, California. 

Show of hands if you'd like to sing on a Mariah Carey track? Well, if you're Justin Bieber, you don't wait to be asked -- you just go for it.

Mariah Carey Flirts Her Way Through Justin Bieber's 'All I Want' Video

Remember, the two collaborated before (for a very special version of "All I Want for Christmas") so they're basically old friends, probably. So when Mariah Carey and French Montana were working on a new song in a Hollywood recording studio Thursday night (July 30), the Biebs just showed up and jumped in, adding some vocals, per TMZ.

Apparently they were fans of his work and he'll be featured in the yet-unannounced track. Stay tuned!

French posted an Instagram pic of the crew: