Christina Applegate Baby Girl Sadie Grace Cover PEOPLE Magazine

Christina Applegate debuted her new daughter Sadie Grace on the cover of PEOPLE Magazine this week.

The former Married With Children actress gave birth to her daughter with her 41-year-old fiance Martyn LeNoble, on Jan. 27, and says the moment was deeply “profound” for her.

“I felt my heart literally open up for the first time and like wrap itself around her,” Applegate, 39, said, adding that baby Sadie has “changed her life.” “I want to be the ultimate burper and diaper-changer, I want to be the ultimate at all of it. Sometimes I stand there going, ‘I’m not doing any of this right!’ And then I get this big man belch out of her and I go, ‘Ah, we accomplished this together.’”

Christina underwent a double mastectomy after battling breast cancer in 2008 and she says it is only now that she’s a mother that she feels completely “healed” from the ordeal.

“I’ve had to talk about that word [cancer] more than I’ve ever had to talk about a word in my life. After a while you’re like, ‘There’s got to be something else to me.’ Yeah, now I’m a mom. She’s healed me in so many ways. She’s just made my life so much better. She’s opened my whole soul. I felt my heart literally open up for the first time and like wrap itself around her. It was profound. And I’m more in love with her every minute of the day.”

Catch Christina on the big screen alongside Owen Wilson, Jenna Fischer and Jason Sudeikis in Hall Pass, opening Feb. 25.