May's comments, made during an interview
with the BBC Tuesday, were made following reports Juncker accused her of being delusional over Britain's departure from the EU.
Referencing a jibe made during her leadership campaign last year by veteran Conservative Party politician Ken Clarke, May said, "I think what we've seen recently is that at times these negotiations are going to be tough."
"During the Conservative Party leadership campaign, I was described by one of my colleagues as a bloody difficult woman. And I said at the time the next person to find that out will be Jean-Claude Juncker."
On Monday, German newspaper Frankfurter Allgemeine
published a report claiming that Juncker had called German Chancellor Angela Merkel
to say that May was "deluded" about Britain's exit from the EU -- an accusation that May dismissed as "Brussels gossip."
May and Juncker met last week for talks that had been intended to pave the way for formal Brexit negotiations. But Downing Street has been left picking up the pieces following the disastrous encounter, which led to the EU side claiming British officials are in a "different galaxy."
May also used the interview to confirm that, if she wins the election, she has "no intention of doing anything other" than serving a full term until 2022.
Prime Minister May unexpectedly called the snap election
less than halfway through her government's five-year term, in an effort to strengthen her hand in negotiations for Britain to leave the European Union
. The UK voted last year to leave the 28-nation EU in a referendum, and the so-called Brexit issue is set to dominate the election campaign.
The announcement marked a U-turn for the prime minister, who had previously said she would not seek an early vote.
May's Conservative Party is currently leading the opposition Labour Party by a large margin, according to the latest opinion polls.
Three polls published at the end of last week suggested that about twice as many people plan to vote Conservative as Labour. The Liberal Democrats, UK Independence Party and Scottish National Party currently trail behind the two main parties.
UK parliament dissolves
The UK parliament officially dissolved
at one minute past midnight on Wednesday and will not resume work until after the general election on June 8.
May is visiting Queen Elizabeth II at Buckingham Palace Wednesday to gain formal approval for the dissolution.
By law, parliament is dissolved 25 working days before an election takes place. Lawmakers are stripped of the privileges of being a member of parliament, and if standing for re-election, must campaign alongside other candidates.
Government ministers remain in charge of their departments until after the result of the election is known and a new administration is formed.