Even will.i.am's family call him by his adopted name and he "can get hostile" if people don't use it.
The Black Eyed Peas singer and producer - who was born William Adams - has been using the alternatively punctuated version of his first name since the start of his career, and even his family have adopted to using it.
He said: "Not even my family call me William. And only government officials or border guards ever give it to me with the full Mr William Adams. But that's not me. It might say that on the paperwork, but that's not me. I'm will.i.am. If anyone says different then I can be quite hostile.
"I've tried explaining it at immigration before, 'I am not the piece of paper you have before you, I am someone else.' They don't get it."
will.i.am also said he misses being at home with his family, and the local cuisine in East Los Angles, where he grew up.
He added to Q magazine: "I've heard most people end up living no more than 30 miles from where they grew up. I'm not in East Los Angeles anymore, but I miss it. I never had tacos better than they got there."