London’s benchmark index closed 1.4% higher on the day, with mining companies leading the way thanks to a softening dollar.
The King, who arrived in London this afternoon, is due to meet new prime minister Liz Truss later in the day and make a televised address to the nation, which he is due to pre-record, in the early evening.
He will pay tribute to the Queen and pledge his duty to his service as the new sovereign.
Elsewhere, the London Stock Exchange (LSEG.L) confirmed that markets will remain open as normal during the official period of mourning.
It said it would notify markets of any subsequent changes to operating arrangements via a further notice, adding that it recognised public bank holidays in England and Wales.
It is expected that the funeral of Queen Elizabeth will be a public holiday.
Naeem Aslam, chief market analyst at Avatrade said: “Investors are digesting the sad news of the Queen’s death in the UK and contemplating Federal Reserve chair Jerome Powell’s most recent statements on inflation.”
US stocks ended with modest gains on Thursday, recovering from early losses after the European Central Bank’s (ECB) rate hike announcement, and comments from US Fed chief Jerome Powell.
He said that the American central bank must continue to act "strongly" to cool demand and contain price pressures.
The New York Stock Exchange (^AMZI) and Nasdaq both observed a moment of silence on Thursday to honour the Queen.
Elsewhere, stocks in Asia edged up on Friday, following an advance on Wall Street as traders prepared for further central bank interest rate hikes.
In Tokyo, the Nikkei (^N225) climbed 0.5% while the Hang Seng (^HSI) surged 2.8% on the day, and the Shanghai Composite (000001.SS) closed 0.8% higher, despite lower-than-expected inflation data out of China overnight.
The dollar fetched 143.78 yen in early Asia trade, against 144.27 yen in New York late on Thursday.