It was pushed back from its original date of Monday to give more time fort the PM to firm up her shaky premiership, and she signalled she is "confident" of getting the Queen's Speech through the Commons.
The leader of Britain's House of Commons says the state opening of Parliament will take place on June 21.
The announcement comes as British Prime Minister Theresa May continues to court the Democratic Unionist Party in a bid to secure an alliance to remain in power.
Brexit Secretary David Davis said parts of the Tory manifesto had to be "pruned away" because they would not command support from the Commons.
The news suggests that Prime Minister Theresa May is close to settling a deal with the DUP, over which talks have been running for the past few days.
The nationalist Sinn Fein and SDLP and the cross-community Alliance have all made clear Northern Ireland Secretary James Brokenshire can not chair the ongoing process to restore power-sharing at Stormont due to the perceived conflict of interest.
Sinn Fein president Gerry Adams said he "told Theresa May directly that she is in breach of the Good Friday Agreement" by undermining the United Kingdom government's role as an impartial guarantor.More news: Tigers put DH Victor Martinez on DL with irregular heartbeat
"However, while talks are ongoing, it's important the government gets on with its business and we are confident there will be sufficient support across the House for passing the Queen's Speech".
"There is very little time left".
The parties have reached "broad agreement" on the principles of the speech.
The Liberal Democrat northern isles MP asked: "If the government cannot even secure a deal with the DUP, how on earth can they get a deal with the European Union?"
But the source confirmed there was no need for a deal on a so-called "confidence and supply" arrangement to be sealed in order to press ahead with the Speech, and said Mrs May wanted the Government to "get on with its business".
DUP leader Arlene Foster, who met Mrs May in No 10 on Tuesday, is understood to have returned to Northern Ireland leaving her deputy Nigel Dodds to represent the party at Thursday's meeting.