Edie Falco on saying goodbye to "Nurse Jackie"

Showtime's "Nurse Jackie" is injecting dark humor into the serious issue of prescription drug addiction for its seventh and final season. Edie Falco, who plays nurse Jackie Peyton, said she loves working on the show, but trusts that it's time to walk away at the conclusion of this season.

"I'm such a worker bee and have been since I was a kid, I would do this forever. But when they say 'You know what, let's walk away while people hopefully want to see it,' you know," she said Tuesday on "CBS This Morning."

Falco's character is a lying, cheating ER nurse--who's also a functioning addict.

"I think those are the most dangerous kinds of addicts, because they can get away with it for so many years as the disease of addiction sort of eats away at them," she said.

With Jackie's addiction fully exposed, she is fighting to keep her job and nursing license by being drug tested at work. But as usual, nothing is easy for her.

Falco, a recovering alcoholic herself, has been sober for two decades and can relate to her character.

"There's so much denial going on ... which was why it's so easy to lie, is you can convince yourself of these things. Some part of Jackie knows that things are bad, but I think in order to get through the day she's got to put it behind her," she said.

She said it's not a tough character for her to play.

"I loved it. She really did so much without worrying about the ramifications. And I'm so not that person that it was actually sort of refreshing to do it and darn the consequences if you will," she said.

Falco, the only woman ever to win an Emmy for lead actress in both a comedy and a drama, is not only known for her role as Nurse Jackie, but also as Carmela from "The Sopranos."

Where does "The Sopranos" ending sit with her?

"Talk about trusting the people in charge. There was so much that went on. I have no idea what it means, what it's about," Falco said. "So when I read the thing I thought, I don't get it at all. Life goes on with 'The Sopranos,' but as the viewing audience, we are no longer privy to it. Which is just annoying enough."