The Prime Minister confronted Donald Tusk during a meeting in Brussels today and told him his controversial "hell" remarks were "not helpful".
Speaking to Tusk, Ms May said his comments had caused "widespread dismay in the United Kingdom".
The European Council president said yesterday that there was a "special place in hell" for the politicians that had promoted Brexit without a "sketch of a plan how to carry it".
An image of Ms May and Tusk posing for an official photograph today has been circulating online, with many social media users commenting on the pair's "frosty" body language.
"Great to see May and Tusk have clearly kissed and made up...," wrote one Twitter user.
Another posted: "Oh, dear! Nothing screams 'Divorce' more than these pictures. Frosty!".
The Prime Minister was visiting Brussels today in an effort to further Brexit negotiations, meeting with Tusk, European Commission president Jean-Claude Juncker, chief negotiator Michel Barnier and other representatives of the European Parliament.
- Read more: Nigel Farage: Donald Tusk was 'thinking of me' with his 'special place in hell' remarks
- Read more: British citizens are 'thin-skinned' if they are outraged by Tusk's comments, says Lord Peter Hain
Ms May reportedly clashed with Tusk and Juncker in meetings, but assured the public that Britain would be leaving the European Union on March 29.
She described today's discussions in Brussels as "robust but constructive" and insisted she was determined to "negotiate hard" over the coming days to secure legally-binding changes to the Withdrawal Agreement which will render it acceptable to Parliament.