Johnny Cash's Daughter Rosanne Shares Throwback Photo of Late Singer with King Charles: 'Too Good'

Rosanne Cash/Twitter King Charles and Johnny Cash

Rosanne Cash is sharing a never-before-seen photo of dad Johnny Cash and King Charles III.

On Monday, Rosanne, 67, posted the decades-old image of Charles, now 73, and Johnny, who died in 2003 at age 71, sharing a moment as they stood together, looking off-camera.

"I've been debating all day whether or not to post this photo, but it's just too good to keep under wraps," wrote Rosanne, who posted the photo amid Queen Elizabeth's funeral.

"I expect a lot of captions, but none I haven't thought of already. But go right ahead," she added.

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BBC America King Charles III

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King Charles recently became monarch upon the death of his mother, Queen Elizabeth, who died at age 96 on Sept. 8 at Balmoral Castle in Scotland.

For more on Queen Elizabeth's funeral, listen below to our daily podcast PEOPLE Every Day.

Monday marked the Queen's state funeral at Westminster Abbey, followed by a committal service at St. George's Chapel in Windsor and, later that day, a private burial at King George VI Memorial Chapel, part of St. George's.

RELATED VIDEO: King Charles Leads Procession to Queen Elizabeth's State Funeral at Westminster Abbey

During the funeral, King Charles and his sons, Prince William and Prince Harry, each appeared "deeply emotionally affected," an onlooker told PEOPLE on Monday.

Lesley Garven MBE, manager of the Blind Veterans UK, said that the monarch and his sons appeared emotional during the services.

"They were flushed. You could see that William and Harry and King Charles were deeply affected," said Garven. "Really deeply emotionally affected by the whole thing, and that really touched me."

"They were obviously holding it together, but when you are so close to somebody you can really feel it and see it, and I think that was probably quite ... it was human. It was real human feelings," Garven added. "Being in there was quite up close and personal and intimate. And it was that whole feeling of, 'This is somebody's mother and grandmother.' Below the pageantry, you could really feel it. The real, raw feelings of people."