Welcome to Times Online's live G20 blog.
We're going to be bringing you news as it happens: from world leaders and The Queen, to Downing Street dinners and what's happening on the streets of London.
And we want to hear from you...
Either send your comments via this blog or send us a message on Twitter @Timesonline
To start things off, why don't you have a go at writing your own G20 Communiqué for Times Online? Keep it short, keep it sharp and tell the world leaders what you think they should do. Click here to enter.
Here's what you can expect over the coming days: G20: the schedule of events
The Obamas are on the way. They have boarded Air Force One and are expected to touch down at Stansted Airport just before 8pm.