Eddie Izzard, Liam Neeson, David Walliams and Russell Brand were watching from the green room, where Harvey Weinstein chatted to Chris O'Dowd. Jimmy Carr was larking around backstage filming links while Mumford & Sons got ready in the room next to Rashida Jones.
They - and 30 or so of their peers - were at New York's Radio City Music Hall on Sunday night for one simple reason: Amnesty International's Secret Policeman's Ball.
Amnesty's challenge back in April 2010 was simple. How, with no media money, do you raise awareness with a new generation of potential supporters, taking their fast-changing media behaviour into account in the process? Having no traditional media is actually one of the most refreshing places to start any strategic and creative process - the answer to that question was never going to be a TV ad.
The audience that Amnesty was looking to connect with gives the vast majority of their attention to entertainment (and each other). They watch it, comment on it, share it and, in some cases, fuel it. Sunday's show represented the start of a series of conversations for Amnesty with a new audience - and not just comedy and music fans.
Amnesty had a sleeping giant: the Secret Policeman's Ball. A cultural property it owns, it was originally conceived against many of the same objectives we had - awareness being the most important. Through the balls, Amnesty has a rich history with entertainers and musicians.
The 50th anniversary presented the perfect platform for reinvention, and changing location was key. We felt that audiences in the US and the UK were closer than they had ever been before - particularly in entertainment terms. We chose New York, and Radio City Music Hall, because they were iconic to both audiences.
The key to last Sunday night's event - and tomorrow's (Friday's) broadcast on Channel 4 - was people. It's as simple as that.
With Kit Hawkins, my partner, we worked with Andy Hackman, Kerry Moscogiuri and the Amnesty team for several months on strategy. The project's second phase began when Lily Sobhani came on board as an executive producer. Lily's background is in producing huge, live broadcast events - Live Earth, Live 8 and the opening ceremony of the World Cup. We then brought in another executive producer, Aaron Grosky, and Control Room - one of the world's leading live event production companies. Next up was DJ Javerbaum, the head writer on Jon Stewart's Daily Show for eight years, who joined to head the writing team. Beth Earl, an executive producer, and the creative producer, James Serafinowicz, became the driving force behind connecting with talent and, together with DJ, we defined the tone and creative for the show.
With Amnesty, we chose the platform of free speech because of all the human rights in the Universal Declaration of Human Rights, it's the closest connected to entertainment and comedy, and most accessible if you're new to the subject.
We were thrilled that the exclusive US broadcast partner was Epix, the premium TV venture of Viacom, Lionsgate and MGM. Given Epix's focus on a younger audience, the event put the spotlight on free speech for many of them perhaps for the first time. It was broadcast live and streamed online at EpixHD.com and via Epix apps on the Xbox 360 and Roku.
Channel 4, the long-term partner for the ball, brought its best game and talent. Co-productions can be notoriously difficult - not this one. If anything signalled the common ground between the two cultures, it was Sunday's show. The opportunity was bigger than any regional nuance - if it was there at all.
Social media was at the heart of our plans to introduce a new audience to Amnesty as an organisation they can approach, have a conversation with and believe in. On Saturday afternoon in a New York hotel, Peter Serafinowicz was Tweeting pictures of himself and Walliams doing last-minute changes to scripts, bringing the audience into the conversation about the content that 24 hours later would be up on stage.
There was a moment backstage on Sunday night an hour before we went live where it all felt weirdly familiar. Reggie Watts, Paul Rudd, Matt Berry and Peter Serafinowicz made last-minute checks to their material. The Channel 4 team were starting their links and clearly enjoying the process while their Epix counterparts set up for their interviews. A small army raced around in headsets in a general atmosphere of collective excitement: it didn't look a million miles away from those original documentaries.
And after it was all over, there was a surprise final act: the spirit continued at the after-party at the Mother New York offices - in large part because there were no cameras. Jack Whitehall and Berry chatted with Winston from Mumford & Sons, while Brand blended in with the crowd and Sarah Silverman joined Coldplay downstairs. The New York institution Jonny Santos provided the music. Izzard and Carr came with mates and stayed, as did Seth Meyers, Jason Sudeikis and the Saturday Night Live gang. Seeing some of the biggest names in comedy and music hanging out with guests and friends at Mother NY reflected the spirit of the night.
Effectiveness will be judged in the long term. Canongate is publishing a book on the history of the ball in September; DVD and video-on-demand releases are still to come alongside international TV distribution, as well a wealth of material shot backstage on the night. Amnesty has many opportunities over the next 12 months to keep its narrative running.
The biggest thanks, though, goes to the 39 performers. Just as the Pythons and friends did in the 70s, they gave their time, energy, talent and audience for a tremendous cause. The hope is very much that this heralds a new generation of Secret Policeman's Balls and, in doing so, makes sure that a vital organisation not just survives in a fast-changing culture but flourishes.
You can watch Amnesty International's Secret Policeman's Ball on Channel 4 at 10pm tomorrow, Friday 9 March (#secretball).
Al MacCuish is a creative director at Mother and executive producer of the Secret Policeman's Ball