According to Spanish media, the monarch will arrive at an unconfirmed date in June.
It would be the first visit by Spanish monarch to the UK in more than three decades.
King Felipe had accepted an invitation from Queen Elizabeth in December 2015, but it was postponed following Spain’s political deadlock that saw it unable to form a government for almost a year.
The visit will come at a time when the UK will be looking for support from EU allies in its Brexit negotiations.
There is speculation as to whether the king will raise the issue of Gibraltar during the trip.
At the UN assembly last year, he said: “I invite the UK, on this first occasion at the UN after Brexit, to end the colonial anachronism of Gibraltar with an agreed solution between both countries to restore the territorial integrity of Spain and bring benefits to the people of Gibraltar and the Spanish area of Campo de Gibraltar.”