There were also Ludacris, Usher, Akon, David Guetta as well as Ke$ha on the performers line-up and the 'Twlight' cast in attendance.
Star-studded concert of KIIS FM's Wango Tango which features the likes of Justin Bieber and Adam Lambert has been captured in a number of pictures. The Canadian singer is snapped wearing a gray military jacket and dog tags necklace, while the "American Idol" alum is seen sporting two-button black tuxedo.
"The vibe is 'Where is Justin Bieber?' - that's the vibe," Ryan Seacrest told MTV backstage about who the highly-anticipated performer was. "All the girls that are hanging out here, even the ones that work for us, are like, 'Have you seen him?' I'm like, 'I'm right here.' They're like, 'No, no. Justin Bieber him'."
Justin opened his set with "Love Me" and continued with "One Less Lonely Girl", "Somebody to Love", "U Smile" and "One Time". He also sang and danced along to Michael Jackson's classic "Wanna Be Startin' Somethin' " and covered Aerosmith's "Walk This Way".
The 16-year-old pop star serenaded one lucky female fan, handed her with a bouquet of flowers and gave her a big hug before sending her back to the crowd. Prior to exiting the stage to give other singers chance to entertain the concertgoers, he performed solo drums and ended his set with "Baby".
As for Adam Lambert, he rocked the Los Angeles' Staples Center with a set of his songs "Whataya Want From Me", "Fever", "Sleepwalker" and "If I Had You". Writing on his Twitter, he stated, "Wango Tango! I love my Band and Dancers!!! Thank you Monte, Tommy, LP, Cam, Brooke, Terrence, Taylor, Sasha!"
Other musical guests at the Saturday night gig were Ludacris, Usher, Akon, David Guetta, Ke$ha and more. Celebrities coming to watch the concert, meanwhile, included Ashley Greene, Nikki Reed, Stephanie Pratt, Kristin Cavallari, David Hasselhoff, Brody Jenner and BooBoo Stewart.