Bafta winners Carey Mulligan and Colin Firth attended the aftershow bash hosted by The Weinstein Company and Universal Pictures at London's Momo.
The actress twins Mary-Kate and Ashley Olsen chatted to Mulligan, who with Precious star Gabourey Sidibe and Josh Hartnett, were still on the dance floor with Harvey Weinstein and a barefoot Claire Danes at 4.30am.
Hartnett and Mary-Kate went even further and were in a passionate embrace until the early hours of the morning.
Nowhere Boy director Sam Taylor-Wood and her fiancé, Aaron Johnson, sauntered into the party briefly. Up in the Air star Anna Kendrick arrived with Hot Fuzz director, Edgar Wright. Firth stuck close to A Single Man co-star Matthew Goode, preferring to hang out in the corner.
They were joined by Rebecca Hall, Matt Dillon, Rachel Stevens, Kristin Scott Thomas and Noel Clarke as well as Inglourious Basterds' Christoph Waltz, who won best supporting actor.
Most of the guests came straight from the official post-Bafta party, hosted by Soho House at the Grosvenor House Hotel, where Little Boots, aka Victoria Hesketh, and girl band The Saturdays performed for guests, including Anne-Marie Duff, Tamsin Egerton and Jonathan Rhys Meyers.
Twilight co-stars Robert Pattinson and Bafta rising star winner Kristen Stewart left that party together, having kept their distance on the red carpet. After months of speculation about a romantic link, Pattinson has since confirmed they are dating.
"It is extremely difficult, but we are together, yes," he said. "We can't arrive at the same time because of the fans. It goes crazy. This was supposed to be a public appearance as a couple but it's impossible. We are here together and it's a public event but it's not easy. We have to do all this stuff to avoid attention."