She said: "Our opponents believe that because the Government's majority is so small, our resolve will weaken and that they can force us to change course".
"In a veiled reference to last June's referendum vote to leave the European Union, May said: "[The] only way to guarantee stability for years to come is to have an early election".
"The country is coming together, but Westminster is not". If the election is backed by two thirds of country's Members of Parliament, it will go ahead on June 8 - roughly three years before the next election was due.
"It is hardly likely that the Conservatives will not win the election and so it will provide her with a clear political mandate to take the country into Brexit negotiations".
"Hopefully this will result in less unease around Brexit in the publics' eyes which can only be a good thing for our industry". She added that her decision wasn't "about political games" but "about what is right for the country".
The announcement has stunned Westminster, particularly as it follows months of insisting by May's ruling Conservative Party that an early general election would not be called.
May's spokesman, speaking to reporters ahead of the return of Parliament the following week, said there was "no need" for another general election following the one in May 2015.More news: Fate Of The Furious Opened Bigger Than Star Wars; You're Welcome
The prime minister's own personal ratings also dwarf those of Labour leader Jeremy Corbyn, with 50 percent of those asked saying she would make the best prime minister.
She said she would introduce legislation on Wednesday to pave the way for the early election. The European Commission has said it wants the exit talks to be concluded by October 2018 at the latest.
When the Conservatives won the 2010 general election, May was named home secretary, the hardest job in government which has wrecked a string of other political careers.
The British pound has fallen amid mounting speculation that Prime Minister Theresa May is planning to call an early general election. May had full support of Cabinet and had spoken to the Queen Opposition parties say they will not block move to hold election on June 8.
She took advantage of the brief meeting unfolded on Downing Street to mention the British Government has the flawless plan to negotiate the terms of the Brexit but they require the right "political unity" from London, informs Reuters. Her office gave no indication on the subject of Tuesday's statement.
Such statements are generally reserved for major news, such as resignations and election calls.