Here's the moment the President and First Lady arrived on Air Force One from Ireland - a day ahead of schedule, out of concern over the Icelandic volcano eruption.
Sadly, one of the first things he had to do today was to address the terrible suffering caused by the recent storms in Missouri and the Midwest.
After which, they met with the Queen and observed the Queen's guardsmen on parade.
Here he is teaming up with Prime Minister David Cameron to play ping pong against some students from a South London school.
David Cameron seems to be letting the side down here, I have to say... Bless him, he seems a bit nervous whereas the President is cool, calm and collected. I imagine he'll be more relaxed at tomorrow's press conference - no doubt the sporting element of any photo op is stressful.
More videos to follow tomorrow - I'm especially excited to see the President's speech to the joint houses of Parliament. I can't remember a US President being invited to address a joint session of Parliament in the time I've been here. Although, speech guru Max Atkinson has pointed me to Ronald Reagan's 1982 speech to Parliament as a great moment in Presidential speechmaking.
Let's see what Barack makes of the opportunity.