Kanye West Disses Ray J During Surprise Performance On Jimmy Fallon

West made unannounced run through 'Bound 2' on Monday night's show, taking shots at 'Brandy's little sister.'

When Kanye West wants to pop in, you don't say no.

And when he's dropping by to perform the Yeezus track "Bound 2" with R&B legend Charlie Wilson, backed by the Roots, well, who could resist that? So when Jimmy Fallon tweeted "@kanyewest surprises Late Night and performs "Bound 2" with @theroots and kills it," on Monday night, you knew something special was in the offing.

And Kanye didn't disappoint. In his first-ever performance on "Late Night With Jimmy Fallon" (as well as the live debut of the song), 'Ye let Wilson do the singing first, as the Gap band legend was in fine voice on the opening hook, "I know you're tired of loving, of loving" over majestic piano backing.

Moments later, the Roots kicked in full force, along with a six-voice children's chorus as West leaned into the song's reworked-for-TV opening bridge. In those lines, he took a not-so-subtle jab at his girlfriend Kim Kardashian's ex, Ray J, with a biting new couplet. "Brandy's little sister lame, man, he know it now," he rapped. "When a real brother hold you down you supposed to drown."

Wearing his signature black leather kilt over black leather pants, along with a green tank top and matching jacket, West was his typically fierce self, not censoring all the lyrics to the song and earning a few bleeps from the network censors.

All the while, Wilson soulfully scatted behind the rapper as 'Ye worked the stage, and, near the end of the almost five-minute performance, threw his head back and splayed his arms out to the side as Wilson brought it all home with some ad-lib runs.

Kanye recently announced the dates for his Yeezus Tour, which is slated to kick off on October 19 at the KeyArena in Seattle and feature guest Kendrick Lamar.