updated 12/17/2010 AT 1:00 PM ET
•originally published 12/20/2010 AT 11:45 AM ET
In The Fighter, Mark Wahlberg and Christian Bale claim the most screen time, but there’s no denying their slew of sisters’ scene-stealing abilities.
What you might not have realized is that one of the Eklund women has a famous brother in real life, too. Kate O’Brien, sister to late night TV host Conan O’Brien, plays Phyllis “Beaver” Eklund in her acting debut.
“I work at a school and someone said, ‘They’re casting [The Fighter], you should go down, you look Irish Catholic,’ ” Kate O’Brien told PEOPLE. “I’m one of six, so it wasn’t that hard for me to look like I might have more siblings [in the movie].”
Reporting by ANNE DRISCOLL