It came as the Prime Minister told her cabinet that the UK must and will leave the EU on the scheduled departure date of 29 March, despite growing unease among ministers about the lack of time to pass critical Brexit legislation, even if a deal is agreed.
One cabinet source told the Scotsman on Tuesday that the chances of an extension of Article 50 were growing, while a timely exit from the EU was looking “less likely”.
Downing Street and the EU confirmed that the Prime Minister would hold face-to-face talks with Commission President Jean-Claude Juncker on Thursday morning, following by meetings with the EU chief Brexit negotiator Michel Barnier and other senior Brussels officials.
However, ministers agreed it was a "positive" development that last week's Commons vote had made clear for the first time that Parliament would back a deal if there were changes to the controversial 'backstop' insurance policy for the Irish border.
"The Prime Minister said that our objective now was to secure a legally binding way of guaranteeing we cannot be trapped indefinitely in the backstop," the spokesman said.
"The PM said that the discussions with the EU will not be easy but Parliament has sent a clear message that a change to the backstop is the only way to get the deal approved."
During Cabinet discussions, it was also stressed that the UK would be leaving the EU “on time”, the spokesman added.
Following Cabinet, the Prime Minister traveled to Northern Ireland to deliver a speech aimed at reassuring residents and businesses that the government was committed to avoiding a hard border on the island.
Announcing Mrs May's planned visit to Brussels, European Commission spokesman Margaritis Schinas said: "As you know, what we have is a procedure involving a number of votes which have taken place in the UK Parliament
"On that basis, the Prime Minister will come along to spell out to us her ideas for what happens next.
"President Juncker has been in constant contact with her and will look forward to seeing her... to pursue these discussions.
"But we have to repeat what you are aware of, that is that the EU's position, the Commission's position, is clear that we are awaiting once again to see what the Prime Minister has to tell us."
In Westminster, the working group bringing together Tories from both sides of the party was continuing efforts to agree an alternative to the backstop.
A meeting on Monday involving Brexiteers Iain Duncan Smith, Theresa Villiers, Steve Baker and Owen Paterson, along with former Remainers Nicky Morgan and Damian Green, was described as "detailed and constructive" by the Brexit Department.
But Brussels has restated its opposition to any attempt to reopen the Withdrawal Agreement, insisting the backstop was the "only operational solution" to the border question.