Theresa May is a "tough lady", European Commission president Jean-Claude Juncker said after the Prime Minister boasted she was prepared to be "bloody difficult" with him.
Tensions between the EU's leadership and the UK Government over Brexit have been laid bare in leaked accounts of a fractious dinner between Mrs May and Mr Juncker in Downing Street.
The Prime Minister acknowledged the negotiations were going to be tough after a detailed account in the German press of their meeting suggested Mr Juncker left fearing the negotiations would end in failure.
Asked about Mrs May's comments in Brussels, Mr Juncker said: "I deeply respect the British Prime Minister, I like her as a person.
"I have noted that she is a tough lady, so this is not for the future, this is the real-time description."
Mr Juncker also dismissed a suggestion from Brexit Secretary David Davis the UK could walk away from talks and not pay a Brexit fee.
He said: "I don't think that David was right when he was threatening that he would be ready to go out. My experience in politics always was that those who are going out have to come back."
In an interview with the BBC on Tuesday, Mrs May turned to the description of her by former cabinet colleague Ken Clarke.
She said: "During the Conservative Party leadership campaign, I was described by one of my colleagues as a bloody difficult woman.
"I said at the time the next person to find that out will be Jean-Claude Juncker."