It's not unheard of, but it's unusual enough to be a bit of a surprise. Watson gives a little disbelieving laugh.

"That is a funny coincidence. I can't imagine there are too many detectives named Holmes in the world, but I suppose there being more than one isn't impossible." Absolutely only a coincidence and nothing more. "But look at me, going on without introducing myself. My name is Watson. Dr. John Watson."