Many people have never heard of the Kate O’Brien. At least that was the case up until last night, when Amy Adams made an appearance on Conan, and the 2 chatted about the host’s sister.

Kate O’Brien is Conan’s sister who is breaking into the acting scene. She makes her acting debut in the upcoming film “The Fighter,” which stars Mark Wahlberg, Christian Bale and Amy Adams. O’Brien plays Phyllis ‘Beaver’ Ecklund – the sister of Wahlberg’s character Mickey.

A Conan O’Brien sister in The Fighter? Yes, it is true – Conan O’Brien of late night fame has an actress sister who appears in the new film The Fighter, starring Christian Bale and Mark Wahlberg.

Amy Adams talks about Conan O’Brien’s sister, Kate, appearing in The Fighter, and he says “she did an amazing job and she loved the experience.”

Adams told Conan that to get the real local character, they did the movie with the real people.

Kate, Conan O’Brien’s younger sister, makes her film debut in The Fighter, playing the character Beaver, sister to Mark Wahlberg’s character.

Conan’s sister said there was a lot of physical fighting that they needed to do in the movie – Amy Adams talks more about having to fake fight and her fear of fake punches.