I had one like this. For work I had to get a picture taken. Several of us were queued up for our shots and when my turn came the photographer asked: “Any relation to Sheb?”
I had to laugh and say that we were (very) distant cousins. But it’s one of the only times that’s happened.
My husband’s brother is a local folk musician. Once is a while I get “really…you are his sister in law?!” I always think its very strange.
I worked in a doctor’s office and had a new patient give me her paperwork. Her last name was Lanza - I said any relation to the great tenor Mario Lanza? She, too, was surprised I recognized the name and said he was her uncle.
StG
I know a guy who has the surname Byng. Turns out he is a relative of the ill fated Admiral and he was very impressed when I asked him about it.
Only once: I was at the doctor’s office, and my nurse’s name tag said “Albaladejo.” At the time Jonathan Albaladejo was pitching for the Washington Nationals, and I’d never seen that last name anywhere else so I asked if she was related to him. She wasn’t (but she’d heard of him).
On the flip side, there is a somewhat-well-known jazz drummer with my last name: I’m a jazz singer, and every now and then I meet a drummer who asks if I’m related to him. I’m not. But I posted a comment on his Facebook page about how I sometimes get asked, and he told me that I’m allowed to lie and say that he’s my cousin if it might ever help me. 
I have the same last name as famous singer. I am not related to him, but I have a cousin who shares his first name as well.
So whenever somebody asks “Any relation to…?” I can truthfully reply, “Yes! He’s my cousin!”
…just not the famous one…
I know the nephew of cartoonist Joe Martin (Mr. Boffo, Willy & Ethel), but he has a different last name, so I don’t know if that counts.
I worked at a company where the marketing director’s last name was du Pont, and he was a member of that family.
My maiden name was Earhart, so I got that question a lot. (The answer was yes, she is a distant cousin).
Now I get asked about Ted Nugent. (No idea, but I presume not. It’s a very common name in Ireland.)
I have occasionally been asked if I am related to an Irish author of some renown, and in fact when I was younger used to claim to be so, but I am not and no longer lie about it.
I was once asked if I was related to man with same surname as me I had no idea who the person was, and said that I wasn’t related to him. Turns out he’s some theatrical person of note (if you’re heavily involved in theatre - which I’m not) and he spells his name differently to me anyways…
I was once asked if I was related to Renee Zellwegger as I apparently look like her (I have been told “no you don’t!!”) on a similar note I was asked if I knew <name> (who happens to be one of my brothers) I said yes, that’s my older brother. The asker stared at me, and enquired as to whether I was sure about that? Yes I was quite positive that I do have a brother called <name> and my name is <name>. He kept staring at me like I was mentally ill, so I started naming off other members of my family, and eventually he decided I was telling the truth. The stupid thing was he was asking me about my brother because “you’re the spitting image of him”.
(Yes, my brother hated me so much he’d never mentioned me to his friends)
I’d watch that sitcom.
I met a female human who claimed to have been the granddaughter of a Mr. Cutter, after whom the Cutter brand of insect repellant is named.
Although we don’t have the same surname, I happen to be the grandson of Roger Araujo, a glass expert who developed the first photochromic lenses
One of my coworkers at a job I didn’t last long at was the son of a Canadian author that I really liked. I never said anything to him… I didn’t know what to say. I answered the phone once when Dad called and had a moment of schoolgirl gushiness, but managed to hide it well enough to take a message.
I am the daughter of someone who was well known within a small community. Even 30 years after his death, there are people who recognize the family name and ask if I’m related. Wish I’d been able to exploit being his daughter better, but I was too young when he died to take advantage of it or follow in his footsteps.
Not a surname recognition: I’m a big fan of painter Lucian Freud. Following the death of the great man last year one of my ex’s facebook friends changed his profile pic. The new picture was a distinctively styled oil painting of said facebook friend and this, coupled with a couple of comments on the page commiserating with him for the loss of his Dad, caused my ex to ask “Was your Dad Lucian Freud?” Yes came the reply. To be honest, in retrospect the profile should have given it away (I refer to the family nose).
I have a student named Lauren Eisley. I made a joke, and got a blank look. So I asked her after class if she knew about Loren Eisley, the scientist. “No…” Ever heard of Mos Eisley? “No…” The city in Star Wars? The “hive of scum and villainy” that was named after Loren Eisley? “No…” Well, maybe you’ve heard of a comic book called Fathom? The protagonist has your exact name, as a pun on Eisley’s name. “No…”
I told her to check with her parents, but she doesn’t seem to care.
Doesn’t deserve to be named after a genius.
I used to live in the same community as a fellow named Seth Thomas. Yes, he was a direct descendant of that Seth Thomas.
A) I’ve never heard of him either.
B) It’s spelled Eiseley.
C) I can find no evidence that Mos Eisley was named after him.
D) I’ve never heard of Fathom either.
Please don’t say things like this. Who is Seth Thomas?
I used to have a Seth Thomas metronome. That Seth Thomas?
My son has a friend with the last name of Von Hapsburg. My husband asked, “any relation?” Yeah, he’s related to Archduke Ferdinand and the rest of the gang. Cool. Super nice guy, too.
A guy I work with is a descendant of Ethan Allen, the U.S. Revolutionary War patriot. He doesn’t have the Allen family name, though.
Hmm. Can’t think of anyone else.
I’m sorry! I didn’t mean to be a dickhead. Possibly because, like Theobroma, I had a Seth Thomas metronome when I was a kid, I was very familiar with the Seth Thomas Clock Company.