Guy internet thought was in disguise at the coronation confirms no, he just looks like that
"I look this way all the time," an affable and laughing Sir Karl Jenkins explained to internet detectives

It’s been a week now since the coronation of Charles III, King Of England, ruler of the Commonwealths, Owner Of The Holy Ball And Stick, etc. And while our memories of that joyous day are already fading—as ecstasy always must—the memes, at least, persist. Sure, there was Katy Perry not being able to find her seat, or our ongoing delight at Lionel Richie’s big bright phone case. But our favorite memes from the coronation undoubtedly centered on this guy, who was spotted sitting near Sir Andrew Lloyd Webber during the day’s event:
With his shaggy hair, big mustache, and sunglasses at the event, the guy in question was an immediate focal point for both jokesters and conspiracy theorists, who wildly speculated online that he was some nefarious disguised entity, looking to infiltrating the coronation, maybe stealing the crown jewels—and might even be that notorious mistress of disguise/former Suits star, Meghan Markle, herself.