Britain's King Charles III is expected to address his citizens later today, Friday, a day after the death of his mother, Queen Elizabeth II, at the age of 96, and Buckingham Palace announced a 7-day period of "royal" mourning.

Upon his return to London with his wife Camilla, the new king will address the British for the first time on television, in a pre-recorded message that will be broadcast in the evening at five o'clock GMT.

The new king will meet Prime Minister Liz Terrace, whose official appointment by Elizabeth II on Tuesday was the last constitutional mission the Queen has undertaken in her life devoted to the end of her role.

The new British king shook hands with members of the public outside Buckingham Palace today, after he got out of his car.

Television footage showed Charles and his wife Camilla getting off the royal car to cheers from a crowd gathered outside the palace.

King Charles III and his wife Camilla on their way to Buckingham Palace today (Getty)

Then the king proceeded to shake hands with dozens and look at the flowers that people put in front of the palace in honor of his mother for at least 10 minutes.

Several members of the audience sang "God save the King", and one said, "We love you, Charles."

Charles has become more present in recent months and has represented his mother - along with his eldest son William - due to what the palace described as the Queen's mobility problems.

And he spoke for the first time yesterday evening, Thursday, in a statement, expressing the "great sadness of the family" after the death of "Her Majesty, dear and beloved mother."

"I know her loss will be deeply felt across the country, kingdoms, Commonwealth, and by countless people around the world," he said.

Buckingham Palace has declared a 7-day royal mourning period (Getty Images)

artillery and bells

During the day, 96 artillery rounds are fired in many places in the country, and the bells of St Paul's Church, Westminster Abbey and Windsor Castle ring.

The honoring ceremonies also began at the other end of the world, in Australia and New Zealand, two of the countries of the Commonwealth of which Charles III became president.

Buckingham Palace has declared a seven-day period of "royal" mourning, starting on the day of the Queen's funeral, which has yet to be determined.

And the “royal mourning” differs from the national mourning - which begins today, Friday - and is committed by members of the royal family and employees of the monarchy, as well as the guards participating in the ceremonies.