What to say when you recognize someone mistakenly

[ScottX]

Today I met one foreigner on the street and mistook him for one of myu British friend at first. I said hello to him then I realized that I had made a mistake. I said sorry to him.

In Chinese, in this kind of context, most of us would say “ I am sorry I recognize the wrong person." (recognize the person mistakenly," or say " I am sorry I made a mistake."

I am wondering what English native speakers would most likely say if they encounter such situation.

 

[Glenfarclas]

I would say, "I'm sorry, I took you for someone else" or "I'm sorry, I thought you were someone else."

 

[Andygc]

"I'm sorry, I thought you were somebody else" seems as good as anything.

 

[ScottX]

Thanks a lot.
Now I know how to say in a better way.