The HBO film premieres Saturday
Credit: Jason LaVeris/FilmMagic

Parenthood‘s Erika Christensen is about to step into the center of a media storm – but luckily she’s got Kerry Washington by her side.

Christensen stars alongside Washington in HBO’s Confirmation, which premieres Saturday and centers on the controversial confirmation hearing of Supreme Court Justice Clarence Thomas. Christensen plays Hill’s (Washington) best friend Shirley Wiegand, and says she was able to get to know the real-life Wiegand for the role.

“She’s just so lovely. I find that really, really smart people have a good sense of humor and she fits that bill to me,” Christensen tells PEOPLE. “I didn’t get the sense that she wanted me to play her a certain way. She really was just trying to be helpful. She was thinking up things. ‘Well my husband says I still have a Wisconsin accent because I’m from there,’ and stuff like that.”

Wiegand’s input was invaluable for stepping into the role of Hill’s best friend. As for her onscreen relationship with Washington, Christensen says she and the Scandal star tried bring the casualness of a true friendship to the set.

“There’s such a shorthand, such a casualness between people who know each other really well. That’s what we focused on when we were working. It’s very much like, we didn’t need to over communicate. We were already on the same wave length,” says Christensen. It’s very much like, we didn’t need to over communicate. We were already on the same wave length,” says Christensen, 33.

In addition to celebrating Saturday’s debut of Confirmation, she and husband Cole Maness are preparing for another big milestone – parenthood.

“It’s still rather surreal,” Christensen says of being pregnant with her first child, a daughter. “She’s a little kick boxer in there – she’s big and moving and communicating as far as reacting to music that we play and stuff like that.”

The big question is how her 4-month old puppy will react to the news.

“I love the idea of my daughter looking back at her childhood and growing up with a dog. He’s definitely smart, so we’re hoping he’ll get it,” says Christensen with a laugh. “He’s got plenty of his own toys so we’ll make sure he grasps that this is his sister and not a toy.”

Confirmation premieres Saturday at 8 p.m. ET.