Justin Timberlake and Jessica Biel attended Timbaland's birthday party in NYC last night. Justin dropped by the celebration after visiting BET's 106 and Park. He has been making the rounds to promote his upcoming album, The 20/20 Experience, including a weeklong stint on Late Night With Jimmy Fallon. Justin teamed up with Jimmy and the Ragtime Gals for a barbershop quartet-style version of "Sexy Back" on Tuesday and has also been performing new tracks from the album, which is being released March 19, nightly. Earlier this week, Justin's team broke big news on his Twitter page, announcing that his recent hit with Jay-Z, "Suit & Tie," has become the singer's seventh platinum single to date.