The celebs were in the house Monday night in Los Angeles when Aerosmith and Cheap Trick pulled into Staples Center. Gene Simmons took his kids, Nick and Sophie, and then wrote on his website, "Both [bands] knocked it out of the park. Two of the best voices out there -- Robin Zander and Steven Tyler -- terrific. And [Cheap Trick guitarist Rick] Nielsen, one of my favorite guitarists. And Joe Perry. Backstage, Johnny Depp chatted with Nick & Soph, and so did Trick and Aerosmith… a great night."

And Johnny Depp was not only backstage, but onstage too, joining Aerosmith on "Stop Messin' Around" and "Come Together." Depp makes an appearance on the new Aerosmith album, Music From Another Dimension, and played with them once before on this tour. Also on stage was former Guns N' Roses guitarist Izzy Stradlin, who sat in on "Mama Kin."