This is the same video that @earl of Rochester showed us a bit ago... I do believe that this is the History Room's E of R, and he's just trying to pass himself off as an average blue-jeans-wearing addle pate, when the reality is that he moonlights as a Regency era gent.
But seriously, I love this guy's clothing... I just made a Regency style drop front dress with some elaborate tailoring in the bodice and now I am about to try making one of those cutaway men's frock coats just for the fun of it. It's an amazing look.