The lovebirds stopped by Hollywood hot spot Playhouse around midnight to help J.T.'s producing partner Rob Knox celebrate his birthday.
The singer and A-Team actress drank 901 Tequila (Justin's own brand) and were spotted kissing with a lot of PDA throughout the night. The couple took their love to the dance floor, shaking it to Michael Jackson and a few of Timberlake's own songs.
Also hitting L.A. at night? Sandra Bullock. Read on to find out who she was hanging out with...
Emma Roberts joined Bullock for dinner at the W Hotel's Drai's nightclub in Hollywood. The actresses dined with club owner Victor Drai before moving to a private cabana. Later on Paris Hilton arrived at the club and introduced herself to the Oscar winner. Paris twittered, "She's even more beautiful in person."
Nicole Richie helped celebrate a friend's birthday at gay bar Fiesta Cantina in West Hollywood on Friday. The mommy of two had some trouble getting into the club because she didn't have any ID with her—yup, the bouncer didn't recognize her. Thankfully, another staffer did and she was let in.
Halle Berry enjoyed a girl's night out with several friends at the Well in Hollywood after taking in a movie across the street at ArcLight Cinemas.
Meanwhile, in Las Vegas, Ashley Greene celebrated summer by lounging poolside at Wet Republic. The Eclipse starlet chatted with fans and hung out with friends in a VIP bungalow where they enjoyed Hpnotiq cocktails, cupcakes and sliders.
Also in Sin City were Playboy Playmates Hope Dworaczyk and Crystal McCahill, who hosted a cocktail soiree at Palms Casino and Resort's Mint High Roller Lounge Sunday night before a screening of their E! reality special The Girls Next Door: The Bunny House.
See what all the celebs are up to in our Big Pic photo gallery.