Katherine Jenkins has recorded a version of the new national anthem, God Save The King, as Charles has become King.
The 42-year-old classical singer said it was a "huge honour" to be selected to record the national anthem for BBC Radio 4, which will be the first recording since The Queen's death on Thursday.
Katherine, who has performed for the Royal Family and the late Queen on numerous occasions, said: "I have only the fondest memories singing the national anthem for Her Majesty The Queen, memories I will always cherish.
"While my heart is heavy with grief, singing this today for the first time is a huge honour and was sung with the belief that King Charles III’s reign will be happy and glorious."
Katherine recorded the song in a small church in a remote area of Sussex and took a moment of silence and prayer before "singing from her heart".
The recorded anthem closed the extended broadcast of the World At One programme on BBC Radio 4 on Friday September 9.
Singer Katherine has performed on a number of occasions for the Queen, including her 90th birthday celebrations at Windsor Castle in 2016.
She also took part in the celebrations over the Queen’s Platinum Jubilee weekend, including performing at a special outdoor concert at Sandringham alongside the Military Wives Choirs, and appeared in the Songs of Praise: Platinum Jubilee Special.
She was among the stars on the bill for the recent A Gallop Through History event, which was broadcast on ITV and featured stars like Tom Cruise, Dame Helen Mirren and comedian Omid Djalili.
Queen Elizabeth II – the longest reigning monarch in British history – died on Thursday September 8 and Buckingham Palace announced the sad news in a statement later that evening.
It read: "The Queen died peacefully at Balmoral this afternoon.
You can leave your tributes to Queen Elizabeth II here
"The King and The Queen Consort will remain at Balmoral this evening and will return to London tomorrow."
Following the announcement, Katherine was amongst many stars to pay tribute to the beloved head of state.
She shared a series of photos of herself greeting The Queen on her Instagram and wrote: "On this heartbreaking day, my thoughts, prayers and deepest condolences are with King Charles, the Royal family and with my fellow Brits & commonwealth members around the world.
"Your Majesty, thank you for all you have given. You have been a selfless constant in our lives, knowing just what to say in our darkest hours.
"You inspired us with your dignity, your duty and your grace. I am proud to have lived during your reign, honoured to have sung for you and privileged to have known you."
Stars joined in on flooding social media with touching tributes to The Queen as Piers Morgan tweeted: "BREAKING NEWS: RIP Her Majesty Queen Elizabeth II, 96. The greatest Monarch in history, and the greatest of Britons.
"Dignified, humble, wise, stoic, and dedicated to duty & service to the country she loved. Thank you for everything, Ma’am. We will be forever indebted to you."
Dame Helen Mirren, who portrayed The Queen on the silver screen and on the stage, described the monarch as the "epitome of nobility".
In a post on Instagram, the Oscar-winning British actress said: "I am proud to be an Elizabethan. We mourn a woman, who, with or without the crown, was the epitome of nobility."
* This weekend, the Daily Mirror and Sunday Mirror celebrate the life of Her Majesty the Queen with a commemorative special filled with all the key moments from Britain’s longest reigning monarch. Be sure to pick up your copy of the Daily Mirror and Sunday Mirror to get both pullouts.
