It's a silly li'l thing, really. My youngest child's name is Liam because I was looking for an Irish name and Liam Neeson is one of my favorite actors, and he's Irish. When I introduce him, people say "Oh William?" (Granted Liam can be a nickname for William but not in my son's case.
I say "Oh it's just Liam" I spell it, smile and say "Like Liam Neeson!"
"No, like Liam Hemsworth!" Like I said, silly little thing but why say "No" cause really, it doesn't really matter which Liam, so long as the point is made the child's name is Liam. That and the first time I heard it I said "Um, who?" lol. In all fairness I guess anyone who doesn't know who Liam Neeson is might be saying the same thing. Though I don't know many who don't know who he is. Even my DH who doesn't care enough to remember actors names and what they were in knows Liam Neeson.
And FWIW I do know who Liam Hemsworth is now but my first reaction was "Isn't that the guy who played Thor?" Nope, that's his brother apparently! LOL!