Christina Applegate on learning the power of saying 'no'

The actress says she was "a people pleaser" until she learned how to say no.

Christina Applegate began her acting career before she could even speak, appearing in a commercial for Playtex baby bottles at only 3 months old.

“My earliest memories were when my mom would put me in the plays that she was in because she couldn't afford a babysitter...she was part of this theater group,” Applegate told ABC News’ chief business, technology and economics correspondent Rebecca Jarvis.

She added, “They lured me onto stage with M&Ms. I sat there, I think and ate M&Ms and then said something here and there.”

Applegate discovered her own love of theater when she did a play without her mother at the age of 10.

By the time she was 13 she had scored a role in the Fox sitcom "Married...with Children” where she played Kelly Bundy for nearly 10 years.

When last episode aired in 1997, Applegate was in her twenties, having lived out her teens on camera.

“I was in this from such a young age and it just never stopped. It was like a continuum,” she said.

She would go on to star in big budget films like “The Sweetest Thing,” “Anchorman” and “Bad Moms," and went back to her theater roots, making her mark on Broadway in “Sweet Charity.”

“I’ve been working since I was 13 completely straight without a break,” she said.

Now the 46-year-old actress and breast cancer survivor is finally taking a moment to herself, staying out the spotlight and focusing on raising her 7-year-old daughter Sadie.

Looking back on her career, she said that the toughest lesson was “learning to say no.”

“I spent a lot of years yes-ing. [I was] such a people pleaser,” she explained.

When she was diagnosed with breast cancer, Applegate was told by a fellow survivor to learn to put herself first. Applegate recently put that advice to the test when she turned down a potentially big opportunity.

“If something doesn't sit right with you you got to say no. I had a job offered to me a year ago and it was going to be the last summer before she [daughter Sadie] started kindergarten,” she said.

Applegate said the job was “amazing” and “paid better” than she’s “ever been paid” in her life but it would force her to miss the summer with her daughter. She recalled getting a sharp pain in her stomach and chest every time it came to making the decision.

“I was like ‘oh no, my soul is saying no, it's saying no.’ Now it would have been amazing for us financially, for my work...But I said no. And they're like ‘You're kidding’ and I'm like ‘I gotta hang out with her for the summer. It's too important to me.’”

She turned down the job and never looked back.

Hear more of this interview with Christina Applegate on episode 89 of the “No Limits with Rebecca Jarvis” podcast.