Several thousand people gathered in front of Buckingham Palace on Friday, greeted King Charles III.
After spending the night at Balmoral Castle in Scotland, where Elizabeth II died on Thursday, the sovereign returned to London in a Royal Air Force jet before returning to the palace.
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As he got out of the car, he gave the crowd a long wave, shaking many hands.
Charles III is due to record his first royal address, which will be broadcast on television at 7:00 p.m. (French time).
He will be officially proclaimed king on Saturday morning.