Justin Timberlake’s promotional blitz for his new song “Suit & Tie” included his producer buddy Timbaland’s birthday bash at Southern Hospitality, where the dress code for the party required guests to wear “suit and ties.” Spies said Timbaland’s friends, including wife Monique Mosley, Jay-Z, Beyoncé, Missy Elliott, Chelsea Clinton and Jamie Foxx, packed into the Hell’s Kitchen restaurant Thursday night before the birthday boy arrived at 11 p.m. Timberlake rocked up to the eatery, which also celebrated its two-year anniversary, after performing on “Late Night With Jimmy Fallon.” Timberlake’s wife, Jessica Biel, arrived wearing see-through crocheted trousers for the formal affair, while Jay and Beyoncé got on the dance floor. The party included oversize balloons, drinks by Neuro and 2,500 cupcakes. The lower level was transformed into a casino, where proceeds went to Timbaland’s nonprofit, the Always Believing Foundation. We’re told Jay-Z and Timberlake played craps, but Foxx lost his shirt in a hand of blackjack.