Chi Chi Izundu
Newsbeat reporter at Shepherds Bush Empire
Gary Barlow and Bono made surprise appearances on stage
It could well go down as one of the "I wish I'd been there" shows of 2009. War Child presents: The Killers and Coldplay.
Two big rock bands rushing straight over from the Brits, to take it in turns on one stage. Neither of them disappointed.
The Killers opened the show to rapturous cheers and applause, with frontman Brandon Flowers shouting: "We're honoured to be here."
The stage was decorated with palm trees, with lights encircling their trunks.
There were trellises covered in even more lights and a huge K in the middle, which flashed depending on the song.
Mr Brightside and Human got fans going the most. They ended with When You Were Young.
Al Murray came on for a bit of extra entertainment while the set-up was changed.
He didn't fail to let them know who he'd love to see on stage - Queen.
Actress Gemma Arterton was one of many celebs at the gig
He got the crowd singing along to a couple of their songs, including Bohemian Rhapsody.
The classical track Blue Danube played while the lights went down, and then Coldplay came on to huge screams and cheering.
At one point, Chris Martin shouted: "(There are) people that we respect and adore in here. People like Louis Walsh.
"He's our favourite X Factor judge. So let's make this our X Factor audition. And we'll give it 115%."
And that's where he got the whole crowd to do the first verse of Yellow.
Chris also congratulated the Pet Shop Boys, who were in the audience watching.
And they weren't the only celebs who wanted to make sure they caught the gig.
Richard Ashcroft, Sienna Miller, Anna Friel, Natalie Imbruglia, Courtney Love and Gemma Arterton were just a few of the famous faces on show.
Rumours were rife before the gig that there would be surprise guests because Coldplay had been playing Take That on tour and Chris has been 'twittering' about them.
Chris turned to the crowd and said: "The band to see at the moment is Take That. We've just had a really bad day. Didn't win anything at the Brits and we've just come back from Japan.
"Shall we welcome the greatest comeback kid of all time? It's Mr Gary Barlow." And on walked a timid-looking Gary Barlow, who then launched into Back For Good.
The crowd roared and screamed with excitement every word at the top of their voices.
Then Coldplay and Gary put down their mics and were done. Or were they?
The rest of Coldplay came back on stage and Chris introduced The Killers.
Bono and Chris Martin also played at the Brit Awards
Frontman Brandon Flowers had changed out of his stage outfit and was dressed in some skinny jeans, a black T-shirt and a purple hoodie.
And then Chris introduced Bono, who walked on stage dressed in black, and took a bow.
Organiser Ben Knowles revealed that backstage, Chris, Bono, Gary and Brandon sat huddled in a corner discussing which song they should end with, minutes before doing it on stage.
Bono was asking the rest of the guys whether he could quickly rewrite some of the lyrics, but as he was thinking, Chris and the rest of Coldplay were back on stage.
As far as they were concerned their decision was made.
It was The Killers track All These Things That I've Done.
Bono sang parts of the verses and the lines "I've got soul, but I'm not a soldier."
Chris had to run off stage and drag Gary back on to be part of the proceedings.
The gig is likely to live long in the memories of those lucky enough to have been there.
Not only were there star-studded performances from the bands, but also great guests to collaborate on each song.
That's what the War Child Heroes album is all about. Bands having a mash up of others work.
War Child's Heroes album is on sale now.