Allison Janney on third season of "Mom," and versatile on-screen roles

For seven seasons on "The West Wing," Allison Janney played the powerful C.J. Cregg, White House press secretary and later, chief of staff to the president. Janney won four Emmys for the role and continues to add hardware to her mantle.

For the second straight year, she was named "outstanding supporting actress in a comedy" for her role as Bonnie on the CBS show, "Mom," which premieres its third season Thursday. Janney said what she loves most about the show is that behind all the laughter, the acclaimed series also provides an honest look at a mother's flaws and struggles with drug and alcohol addiction.

"Putting that out there and through de-stigmatizing addiction and recovery as much as we can," Janney said. "It's not something that has to be dour and awful and unhappy. Recovery can be freeing and fun and wonderful and I think we're showing that people can go through tough things in life with laughter."

Janney also offered some spoilers for the season opener. Bonnie -- who was given up for adoption -- finds out that her birth mother is trying to get in touch with her. She ultimately decides to meet Ellen, after she lies that she is dying.

"It's a very touching and moving episode, but also, the writers managed to make it hilarious," Janney said.

Emmy and Oscar-winning actress Ellen Burstyn plays Bonnie's biological mother, Shirley. Janney explained that she was initially afraid to meet her new cast member.

On the set of "Mom" with Chuck Lorre, Anna Faris and Allison Janney

"I'm always afraid someone's going to disappoint me if I meet them, or maybe she'd be difficult to work with," Janney explained. "You just want to hold people you admire in a special place and not to burst that bubble."

But Janney said Burstyn "did not disappoint," and working with her only made her "love her more." She displayed her admiration for her co-star and her applauded her professionalism on the set, saying that the show's executive producer Chuck Lorre entrusted Burstyn to do "anything," even changing her lines.

Janney's comedic role in "Mom" starkly contrasts her intimate, steamy sex scenes in the Showtime series, Masters of Sex. She stars as Margaret Scully, a wife who is completely naïve sexually until her affairs outside of her marriage.

Speaking about the versatility of her roles on-screen, Janney said she feels "very lucky and proud" for the opportunity to play such different roles.

Catch the premiere of the third season of "Mom" on CBS Thursday, Nov. 5 at 9/8c.