Maroon 5's MSG surprise: Kanye West

Hollywood Insider traveled east this week to catch Maroon 5 make their arena debut on Wednesday night. And we, along with a sold-out crowd at New York's Madison Square Garden, got a special treat: an appearance by Kanye West, who joined the band for "Heard 'Em Say," the single from West's last album, Late Registration, featuring Maroon 5 frontman Adam Levine as a guest vocalist. Was it planned? Somewhat, but certainly not practiced, Levine told EW. "Kanye was on vacation and we didn't know whether he was gonna be there at all," he said at the band's official after-party atop New York's Bowery Hotel. "We found out about it an hour and a half before the show. No rehearsal, he just showed up and we decided to wing it. And, like always, he delivered. As did we." An extended version of the song, re-christened "Nothing Lasts Forever," is one of the highlights of Maroon 5's latest CD, It Won't Be Soon Before Long, but, despite our constant pleading, don't expect to see it released as a single, like, ever. "We got others," Levine insisted (the ballad "Won't Go Home Without You," is next to go to radio).

Befitting Hollywood's "It" band, plenty of stars were on hand to cheer them on. West's Island Def Jam label-mate, Rihanna, was spotted backstage, while Zach Braff and Levine's most recent duet partner, Saturday Night Live's Andy Samberg, made the after-show scene. Unfortunately, there was no such reprise of their hilarious SNL video spoof, "Iran So Far."