Martin Schulz will be the latest EU chief to visit London after the UK voted to leave the political and economic union, when he meets Theresa May this evening (22 September).
The European Parliament president's trip comes after European Council President Donald Tusk held a summit at Number 10 with May ahead of the Bratislava summit of 27 EU leaders last week (the Conservative premier was not invited).
"The future deal between the EU and the UK must be good for all sides and must be one which allows the UK and the EU to keep working closely together on various aspects," Schulz said ahead of his visit.
"The UK has decided to leave the EU but it will continue to be a European country with values and geopolitical interests which are common to the rest of the continent.
"I will also reiterate that the four freedoms of the single market – goods, capital, services and persons – are equally important. In London I will also stress why the European Parliament favours the earliest possible triggering of Article 50, which is a precondition to opening negotiations."
But May has ruled out triggering Article 50, the official mechanism to split from the EU, this year. She is expected to make the move next year, which would start two years' worth of negotiations with Brussels.
In the meantime, her government is busy planning for the talks. The prime minister has promised not to "give a running commentary" on negotiations, but IBTimes UK yesterday reported that the Department for Exiting the EU has seen its headcount surge by 400% in just two months.
Schulz is also expected to meet Labour leader Jeremy Corbyn and Mayor of London Sadiq Khan during his visit. Corbyn, unlike his leadership rival Owen Smith, had ruled out holding a second referendum to "ratify" Brexit, while Khan has stressed the capital is "open for business".