Barack Obama says America is 'looking forward' to the UK remaining part of the European Union.
The President made the comment as he held talks with David Cameron at the G7 summit in Germany.
He believes Britain plays a positive role within the EU "on a whole host of global challenges".
The British Prime Minister has promised an in/out referendum on EU membership by the end of 2017.
Meanwhile, David Cameron has agreed to increase the number of UK military personnel in Iraq - to support the fight against Islamic State militants.
100 more will train Iraqi security forces to deal with explosive devices - and 25 will assist with training in other areas.
