Prince Charles admitted he’s struggling to keep his suit measurements the same.

The Queen’s eldest son opened up about his size during a visit to the Gloucester workshop of Emma Willis, the person responsible for making the prince’s shirts for several years. When Willis revealed that the British royal has remained the same size, he joked that it’s not an easy thing to maintain.

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“Very kind of you — you’ve got my measurements. I struggle to keep them the same, a never-ending battle,” he quipped, according to People.

Willis recalled how she became the go-to designer for Charles, recalling a moment six years ago when his dresser asked if she would be willing to let him try one of her designs.

“So I went to Clarence House and measured His Royal Highness for the first time, and we’ve been making his shirts ever since,” she explained. “And one of the things we specialize in is very fine Swiss cottons, and he loves lovely soft fabrics.”

Britain's Prince Charles revealed that it's difficult for him to maintain his current suit measurements.  (Abir Sultan/Pool Photo via AP)

The British royal was on hand to help promote Willis’ Style for Soldiers charity, which she founded in 2008 when she began visiting patients at the Military Rehabilitation Hospital. The organization seeks to provide clothing for servicemen and women who faced unwanted medical discharge from the military to help them dress for interviews and other formal occasions.

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“I just wanted to come really to thank you, more than anything, for the wonderful things you do, apart from making fantastic shirts and boxer shorts and everything else. But everything you do for our armed forces and all those who had the horror of being wounded in one way or another, it is a wonderful thing you do,” Prince Charles said during his visit.

The Prince of Wales was all smiles at the event despite being thrust into the spotlight recently as he and the queen worked to hammer out details of his son and his daughter-in-law, Prince Harry and Meghan Markle, deciding to step back from their senior royal duties, relinquish their royal highness titles and live financially independent of the crown.

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Harry was on hand earlier this year for a private meeting between the royals to determine how best to go about the logistics of the big change.