Well, that soldier is definately American. The only British soldier wearing that colour beret would be SAS, and they don’t generally stand around posing for photos...
Wrong shade of tan to be a Ranger beret, plus the flash and shaping are all wrong. Gotta be a Brit.
While the sand-coloured ‘beige’ beret is SAS, some regiments wear a khaki beret which under certain lighting conditions doesn’t look much different.
I can’t get a good view of his cap badge, but it looks like it could be the Yorkshire Regiment and they wear the khaki beret.