King Charles joined Sir Elton John for an episode of the singer's radio show which was aired on the monarch's 78th birthday.
In it, the king joked that they both were "still standing".
The special edition episode of Elton John's Rocket Hour was to celebrate 50 years of The King's Trust.
Britain's King Charles has joked that he and Sir Elton John were "still standing" in a clip recorded for the singer's radio show which was aired on the monarch's 78th birthday.
King Charles had joined Sir John for a special edition of the singer's Elton John's Rocket Hour on Apple Music to celebrate 50 years of The King's Trust and musicians who have supported his youth charity.
During the episode, which was first broadcast on Saturday to coincide with the king's birthday, the pair discussed benefit concerts held in support of the Trust.
This included a Rock Gala held at Wembley Arena in 1986 where Sir Elton performed his 1980s hit, I'm Still Standing.
"I know people in all kinds of circumstances find this song inspiring, not only for its marvellous spirit, but also its message of resilience," King Charles said.
Sir John, who turns 80 in March, replied, "I'm still sitting now, though", prompting laughs from the king.
