"The girls have a big bachelorette party and they all wake up and don't remember anything," Nichols tells TVGuide.com. "The whole episode is them the next day piecing it together, all the different locations and figuring out what they did."
Unfortunately for Julian, the ladies get to have all the fun.
"There was no bachelor party for Julian. I got to say it hurts my feeling a little bit," Nichols jokes.
As for the actor, he has an upcoming One Tree Hill episode to be excited about: his directorial debut. Nichols recently found out he'll be directing the eighteenth episode this season.
"When I get back from the new year I'll start prepping and then I'll shoot that in January," he says.
Check back for more of my exclusive interview with Austin Nichols. One Tree Hill returns with new episodes on Tuesday, Jan. 25th at 8/7c on CW.