Usher Closes Out iHeartRadio Fest Friday With Surprise Guest Chris Brown: Watch

Usher, 2014.
Kurt Iswarienko/Courtesy RCA Records

Usher photographed in 2014.

"He's a friend, he's a brother, he's a passionate artist," Usher said while introducing Breezy.

The first night of the fourth annual iHeartRadio Festival in Las Vegas had many surprises up its sleeve, from a ferocious Ariana Grande-Nicki Minaj duet on "Bang Bang" to an unannounced performance from Alicia Keys to Will.i.am and Pete Wentz joining Steve Aoki during his wall-shaking set. But no unexpected artist earned as many screams as when Usher brought out Chris Brown to perform the latter's current single "New Flame," an appearance that apparently almost didn't happen due to Brown's probation terms.

"I'd like to introduce this young man that I've gotten to know," Usher said. "He's a friend, he's a brother, he's a passionate artist and I have a fortunate opportunity to have shared a song with him."

More iHeartRadio: Watch Taylor Swift Shake Off The 'Frenemies' | Friday Higlights: Ariana, Nicki & More

The result was an instant moment for the iHeart record books, with Usher and Brown's silken vocal harmonies culminating in a dance-off between the two multi-hyphenate performers that ended with Usher setting his high-tops ablaze -- as in, literally on fire onstage (hence the "new flame.")

Though Usher also performed his current singles "Good Kisser" and "She Came To Give It To You" (sans duet partner Nicki Minaj, despite the fact that she played hours earlier), the recent indefinite delay of forthcoming studio album UR suggests that public interest hasn't quite peaked as high as it had for previous Usher album cycles just yet. But with Brown's cameo arguably the best-received moment in Usher's 20-minute closing set, perhaps it's time for Breezy to return the favor as Usher heads back to the studio to finish UR.

Meanwhile, Chris Brown is eyeing a No. 2 debut on next week's Billboard 200 albums chart with the oft-delayed X, which was released on Sept. 16. With a big bow, Brown would notch a sixth Top 10 album in six tries.