The couple arrived at the Hennessy-sponsored bash at Manhattan nightclub Nikki Beach just after 11:30 p.m., less than half an hour before the party was due to end, and bolted hand-in-hand from their SUV through a side door.
They headed straight to the exclusive VIP section, out of sight of partiers including The Hills stars Lauren "L.C." Conrad and Heidi Montag and Timberlake's former 'N Sync bandmate Lance Bass and boyfriend Reichen Lehmkuhl.
In the private upstairs bar, Timberlake and Diaz were cordoned off behind a wall of five beefy bodyguards. Among the select few allowed past: 'N Sync-er JC Chasez, The O.C.'s Rachel Bilson, Hulk Hogan and his family, Jamie-Lynn Sigler and boyfriend Scott Sartiano and, of course, Timbaland, who produced Timberlake's hit "SexyBack."
More VMA Coverage
Around 12:20 a.m., Diaz danced a little dance until a girlfriend reached up from one of the club's lounging beds and gave her bum a tap. Giggling, Diaz headed for Timberlake. After chatting for a few minutes, she put her arms around his neck and they hugged, then shared a private nuzzle in the middle of the jam-packed room.
When the DJ finally played "SexyBack," Timberlake, Diaz and Timbaland sang and danced along. Timberlake told pals how quickly his producer got his vibe: The first time he sang the line "I'm bringin' sexy back" to Timbaland, he said, his response was, "Yeah!" – and that call and response is exactly what's in the song.
Finally, it was time to go, and Diaz followed Timberlake, holding his hand from behind, leaning against him and snuggling into his neck. Even as fans started touching them and snapping photos of them with camera phones, the couple kept smiling as they disappeared into the night.