King Charles joined Elton John for an episode of his Rocket Hour radio show. ( Supplied: Apple Music/Handout via Reuters )
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.
King Charles and Sir Elton John at the Royal Variety Performance in 2024. ( Reuters: Toby Melville/Pool/File Photo )
"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.
"With occasional bits dropping off here and there," King Charles said.
"I know this is a terrible problem as we get older."
Both men have suffered well-documented health problems in recent years, with the king still undergoing treatment for cancer and Sir Elton suffering problems with his eyesight.
When he was the heir, King Charles founded the Prince's Trust in 1976 using his Royal Navy severance pay to help disadvantaged young people prepare for work, find jobs or start businesses.
It was renamed the King's Trust after Charles became king in 2022.
The charity says it has supported more than one million young people since its launch.
Rocket Hour is a weekly show that has aired globally on Apple Music 1 since 2015.
