Her meeting with the 91-year-old monarch later today marks the formal start of campaigning for the June 8 general election even though all political parties have already begun canvassing.
Under the British law, the Parliament must be dissolved at least 25 working days before a general election.
However, the Parliament is "prorogued" several days ahead of being dissolved, meaning all parliamentary business stops but the Parliament still technically exists until dissolution.
After the dissolution, every seat in the 650-member House of Commons becomes vacant and members of parliament temporarily lose all privileges associated with their station.
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May, who received the Parliament's backing last month to hold snap polls, is currently leading in most opinion polls to win a majority mandate for her Conservative party which, she believes, needs to carry Brexit negotiations forward.
Her decision to hold a snap general election took everyone by surprise, including the queen - who will have to "dress-down" for the new UK Parliament opening next month due to shortage of time to rehearse for the event.
The British monarch is responsible for the ceremonial opening of Parliament business every year, which involves considerable pomp and ceremony including being dressed up in flowing robes.
The date also means that the queen has had to cancel the Order of the Garter ceremony when she hands over royal medals at Windsor Castle, for the first time in 30 years.
Buckingham Palace said in a statement that "to allow her majesty to attend in support of the parliamentary and constitutional process, the queen's programme of engagements has been revised.