King Charles III has addressed both Houses of Parliament for the first time as monarch, APA reports citing BBC.
Speakers from both House of Commons and House of Lords offered condolences at a ceremony at Westminster Hall following the death of Queen Elizabeth II.
Addressing the King, Sir Lindsay Hoyle said, "as deep as our grief is, we know yours is deeper."
About 900 MPs and peers attended the ceremony.
At Westminster Hall - which is also where the Queen's coffin will lie in state later this week - the monarch, accompanied by Camilla, Queen Consort, has given a reply in front of about 1,200 people gathered inside.
State trumpeters played a fanfare as King Charles made his way through Westminster Hall and the Royal Standard was raised in place of the half mast.
Addressing the King, Lord McFall paid tribute to the late Queen and said she "captured the imagination of peoples across the globe".
"We remember her commitment, her kindness, her humor, her courage, and her fortitude as well as the deep faith which was the anchor in her life," he added.
"We are proud and humbled to welcome you as King."
Also among the attendees in the hall is Ugbana Oyet, the first black sergeant at arms in the role's history.
Monday's visit to Westminster will also see members of both houses pledging loyalty to the new monarch.
Ed Davey, leader of the Liberal Democrats, told BBC Breakfast he hoped the Queen's passing would be a moment of "unity" for the UK.
"My sense is a real sense of unity, people coming together in their grief and gratitude to the Queen," he said.
After the King flies to Scotland, there will be a procession along the Royal Mile to St Giles' Cathedral. The trip will mark the start of a tour of all four nations of the UK.
His Majesty will lead members of the Royal Family - expected to include the Queen's other children the Princess Royal, Earl of Wessex and Duke of York - as they walk behind the Queen's coffin.
Large crowds are expected in the Scottish capital on Monday for the procession, with city council leader Cammy Day urging people to arrive in the city center "as quickly and early as you can."
At the cathedral, the Royal Family will be joined by a congregation drawn from all areas of Scottish society to attend a service of thanksgiving for her life.
Later in the evening, the King and his family will observe a vigil at the cathedral in honor of the Queen.
Her coffin will remain at the cathedral for 24 hours for public members to pay their respects before being flown back to RAF Northolt and then traveling on to Buckingham Palace.