Why Does Billie Eilish Have a Different Last Name Than Her Brother?

Everywhere you look, Billie Eilish is being celebrated, with due cause. Right by her side is her brother and longtime collaborator, Finneas.

The two are indeed inseparable and seem to share everything on stage and off, except a last name.

Have you ever wondered what Finneas's last name even is? Or if Billie Eilish is the singer's given full name?

Ahead, you'll find out what Billie's last name really is and why it's different than her big brothers. Or is it?

As the Oscar winners explained while appearing on Jimmy Kimmel Live in late 2023, Billie and Finneas both actually share a last name: O'Connell.

But neither sibling goes by their legal last name, for differing reasons.

As Finneas said about his choice to go by his first name only, "Well, my name is three syllables and then, like, our legal last name is another three syllables. It just felt a little clunky. And I’m a big fan of Cher."

As for the singer herself, apparently she has been going by the name Billie Eilish for most of her life. Plus, she doesn't find the name O'Connell to be very sexy.

"It’s just like not the sickest last name. You know what I’m saying?" the always edgy performer told Jimmy during the interview, with her brother also joking the surname would be better suited for a potato farmer.

It seems that being "very Irish" is not the image that the singer is looking to achieve, as she said about her real name, "It’s like very, very Irish. Billie Eilish O’Connell, it doesn’t get more Irish than that."

Despite their conventional last name, the eventual Grammy and Academy Award winning machine made up by brother and sister had a childhood that may not be reflective of most of their fans.

Indeed, the duo was homeschooled by the siblings' parents, actors Maggie Baird and Patrick O’Connell.

As the stars' dad explained in 2019, "Our whole stance was, general knowledge is all. You need to know why the sky is blue, but you don't need to memorize a bunch of esoterica you'll never use."

Meanwhile, would you believe that Billie and Finneas's parents gave up their bedroom so their kids could turn it into a recording studio? The famous pair's parents moved into the living room to allow for their offspring to work on their music — a gamble that obviously paid off!

Finally, consider this interesting tidbit: Much like Giants quarterback Tommy DeVito, Billie reportedly still lives at home with her mom and dad in their California home, despite her immense success. The singer has a net worth as high as $50 million at the time of this writing!

In contrast, Finneas has moved out of the family home. Billie's big brother reportedly owns two homes in The Golden State.